Onions:

Introduction – The Basics:
Onions, Allium cepa, can be divided into three main types – spring onions, maincrop onions, and Japanese onions. These types in turn are available in many varieties. Some varieties of each are:

‘Ailsa Craig’ – a very popular variety of maincrop onion, with bulbs of a large size. Not particularly easy to grow, some say, but a good exhibition variety which has the added advantage of being a heavy cropper.

‘Bedfordshire Champion’ – an old English variety which yields large bulbs with golden-brown skin. This variety stores well.

‘Red Baron’ – another popular variety in the UK this onion, as the name suggests, is a red variety. Stores well and is an early cropper.

‘Senshyu’ – a popular Japanese variety which produces high quality round bulbs.

‘North Holland Blood Red’ – an intensely coloured red spring onion, can also be grown as a bulbing onion.

‘Savel’ – A spring onion with a tall stem which is said to have fewer problems with bulbing.

Planting Site:
As always, due care and attention must be given to soil preparation prior to growing onions. The planting site should be well-drained and in a sunny position, if the soil is too heavy then the addition of organic matter or grit will help to open up the pore spaces and improve the drainage. As with most vegetables, the planting site should ideally be on level ground, however if the ground is sloped then the onions should be planted towards the top of any slope in order to prevent water-logging and maintain good drainage. With regards to pH, onions prefer a neutral to alkaline soil – if your soil is acidic, you should apply lime to help rectify it.

Sowing Times and Methods:
Onions may be grown either from seed or from sets (a ‘set’ is a small, immature onion, with each set maturing into a single onion). Although sets have the advantage of producing, on the whole, onions which offer more resistance to pests and diseases, growing from seed has the advantage of offering the grower more choice in the varieties on offer; seeds are also considerably cheaper than sets and more easily obtainable.

Seeds may be sown from August to April, although sowings in January should be done under glass. Spring sets may be planted between February-April, although if they have been heat-treated (which, because the flower embryo has been killed, reduces the risk of the plant bolting or running to seed) then sowings should be delayed until March at the earliest; autumn sets can be planted between early September to early November. Japanese onions should be sown outside in mid-August, and spring onion seed should be sown at intervals from early April to early June. If the planting site is one with heavy soil, despite cultivation, then spring planting are preferable to those in autumn as the risk of water-logging is further reduced. Sowings made in the autumn are harvested from the following June onwards, whereas spring sowings are harvested from August onwards – this provides the gardener with the opportunity to grow a successional crop.

Indoor sowings of onions are made easier by using modules rather than trays. Ensure that the compost (a proprietary seed compost is sufficient) is moist before sowing about half a dozen seeds per module – this will not cause overcrowding as the maturing bulbs, once planted out, should push apart from one another as they expand in girth. Once the seeds have been sown in the modules, apply a thin layer of vermiculite to assist germination. The ideal temperature range for germination of onion seed, under glass, in January-February is 10°C-15°C, if the temperature in your shed or greenhouse is below that then a heater may be used to correct it.

Planting of sets is done in drills, with each set being placed so that, after being covered with soil, the neck is still visible (protruding over the soil surface). Beware of the fact that birds may try to uproot your sets if too much of the bulb is showing, although once they are firmly rooted this ceases to be a problem – the birds can be deterred by protecting the newly-planted sets with fleece or netting (a miniature polytunnel could also be used but that is more costly). Try to ensure that the soil beneath the bulb (the base of the drill) is of a soft and friable nature and that it is not too firmly compressed when planting the sets as this can inhibit the formation, and spread, of roots. Planting distances should be roughly 5-10cm between each set, with the rows spaced about 25cm apart (see Diagram 1).

Once the seeds or sets have been planted, little in the way of maintenance is required. Control of weeds must be a priority for, with the upright growth of their leaves, onions are poor at weed suppression and are therefore subject to intrusion by and competition with weeds. Control can be asserted simply by hoeing between the rows, and an onion hoe is the best tool for this as it has a small head which is less likely to damage the crop. Over-watering should be avoided as an excess of moisture, especially after mid-July can delay the onions from maturing, which in turn can lead them to deteriorate.

Pests and Diseases:
The pests and diseases which afflict onions are rife, and include onion fly, onion thrips, onion eelworm, onion neck rot, onion white rot, and downy mildew. Bolting is also considered a problem, although it is not a disease but rather the tendency for the onions to flower and set seed before the bulb is mature.

It is the larvae of the onion fly (Delia antiqua) which attack onions, mainly eating the roots although if the infestation takes place in late summer (when the plants are more developed) they may burrow into the bulbs (see Diagram 2). Removal of any infested plants should be done promptly to try and prevent the larvae from travelling into the soil where they will pupate. The adult flies can be discouraged by companion planting, such as with carrots – the theory being that the smell of the carrots will confuse the onion flies, and likewise the smell of the onions will deter carrot flies. The risk of attack by onion flies can also be lessened by growing onions from sets instead of bulbs.

Onion eelworms are tiny worms, about 1-2mm in length, which travel through the soil and enter onion bulbs – this leads to swelling and distortion of the bulb. Any infected plants should be destroyed away from the compost heap. There is no effective chemical treatment for this pest, and if your plot is infected you should avoid growing onions there for a minimum of three years.

Onion thrips, yellow or black-bodied insects about 2mm in length, are another variety of pest which afflict onions. Their presence is marked by the appearance of a fine white mottling on the leaves of the plant, which is usually worse during dry, hot weather – a heavy infestation of this pest can cause smaller crops. To control onion thrips spray with a suitable insecticide.

The first of the diseases mentioned, onion neck rot, is caused by a fungus (Botrytis alii). The disease causes a grey fungal growth around the neck of the onion and causes the tissue to soften. The infected areas start to become transparent, often completely drying-out, followed by the development of sclerotia (which are small black areas of resting fungus which are designed to survive the winter). In order to try and prevent the occurrence of onion neck rot, ensure that any sets bought are from a reputable source, do not grow onions on the same site in consecutive years, and bear in mind that onions with yellow or red bulbs are more resistant than those that are white.

Onion white rot, the second disease mentioned, is caused by another fungus – Sclerotium cepivorum. In the case of this disease, infection is indicated by dense, fluffy white growth around the roots and base of the bulb (the basal plate area). This disease is very serious as there are no chemical controls available and no resistant varieties have yet been bred. Remove any infected plants as soon as possible and dispose of away from the compost heap. If infection is found then you should refrain from planting onions (or related crops) on that site for at least eight years.

The final disease mentioned is downy mildew. Another fungal disease, caused by Peronospora destructor, downy mildew is more likely to occur when dampness and excess humidity are a problem. The disease causes grey, fluffy growth to appear on the foliage which may subsequently die back. If infection occurs early in the growing season then the bulbs may not attain their full size. All infected foliage should be removed and destroyed, and the grower should use a fungicidal spray containing mancozeb.

Harvest and Storage:
Harvest, whether of a summer or winter crop, takes place as soon as the foliage of the plants has started to turn yellow and die back – the bulbs can be lifted earlier if necessary but they will, naturally, be smaller than those left until full maturity. One can harvest onions by whichever method they prefer, some gardeners believe that you should sever the roots with a knife so as to prevent wounds which could be conduits to infection, others simply lift the bulbs with a fork. Although ripening can be hastened by bending the tops over, this can lead to problems developing when storing the onions. When lifting the crop, keep an eye out for any which have developed thick necks – as these will not store well they should be used as soon as possible.

The drying and storage of the bulbs is a simple matter made complex by the multitude of methods and opinions on the subject. An easy yet effective method is to lay the bulbs (with the foliage still attached) on a dry surface in a warm place (warm, but not too hot) for a few weeks. If the weather is wet, then place them in a cold frame in the shade to dry.

Once the onions are dry, and one must make sure that the foliage is completely dry to prevent any problems, they can be stored quite easily in nets or on trays – with bulbous onions one can even plait them into strings.

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Peas:

Introduction – The Basics:
As with other vegetables, the first consideration must be the preparation of the planting site. Peas, like other members of the legume family, prefer a neutral to alkaline soil pH (preferably, in the case of peas, of pH 7) – if the soil in which one plans to grow them is on the acidic side, then an application of lime will help. Peas also perform better in a soil which has been enriched with a goodly amount o organic matter (such as well-rotted manure or garden compost). Make sure that the soil has been well worked/dug before planting and that drainage is good. If the soil is prone to water-logging then work in some sharp sand to improve the drainage of the water; if the soil is sandy and poor at retaining water, then the addition of organic matter will improve cohesion and help to retain moisture.

Sowing Times and Methods:
Sowings can be made either in pots, or directly into the ground. To obtain a very early crop one should sow seed of an appropriate variety directly into the prepared plot during late October/early November under cloches, or in early March. A variety of first early such as ‘Kelvedon Wonder’ is ideal for this, and may also be sown direct into the ground without need for cover in early March. Early peas may also be sown in pots throughout late January/early February and be brought on indoors before planting out under cover in March. These plants can be expected to be ready for harvest in May at the earliest. Successional sowings can then take place from March onwards, with a variety such as ‘Onward’ being good as a second early crop, and varieties like ‘Jaguar’ and ‘Balmoral’ as maincrop plants. The latest sowing dates are usually around mid-June, for harvesting in September/October.

Seeds should be sown in v-shaped drills (5-7.5cm), with 60cm between rows for low-growing varieties and 90cm between rows for tall varieties.

General Care:
Birds can be a problem when the seedlings start to emerge: covering the plot with cloches or mini polytunnels will provide protection both from avian predators and from particularly harsh weather. When the seedlings are 5-7.5cm tall you will need to provide a form of support for them. This is usually in the form of ‘pea sticks’- twiggy hazel twigs set either upright or at an angle of 45°, although plastic netting strung between posts will also do well to support the plants (see Diagram 3).

Pests and Diseases:
Cydonia nigricana, the pea moth (see Diagram 4 for life cycle of this insect), lays its eggs on the flowers of the plant and the caterpillars which hatch subsequently burrow into the pods and feed on the peas. Although the eggs themselves are small and difficult to spot (with a magnifying glass you may see them – tiny green scales on and around the leaves), you may recognise the moth which is small and of a grey-brown colour with white tips on its wings. The caterpillars are pale yellow (with black heads and brown dots) and approximately 9mm long – they will burrow into the pods, but as they only require one or two peas to feed on, depending on the severity of the infestation you may be able to save much of the crop by careful sorting. As the caterpillars move inside the pods, the timing of any spraying is critical: spray with an appropriate contact insecticide (e.g. Bio Fenitrothion) about a week after the first flower appears, and follow up with a second spraying after a further ten days. Prevention can be attempted by covering the plants with insect-proof mesh when they are in flower, which also helps prevent damage from birds. Late and early sowings can also be effective in avoiding pea moth damage. Affected plants can be added to the compost as the caterpillars abandon the plant and burrow into the ground to cocoon – digging over the soil in the autumn will hopefully allow birds to take care of cocoons which remain in the ground.

Pea thrips are another pest which may be a problem. They cause browning and distortion of the pods, and silvery patches on the foliage – you may be able to spot minute insects (black/yellow) on the plant. They can be dealt with by spraying with an insecticide containing fenitrothion or permethrin. As the nymphs pupate in the soil to over-winter, digging over the area in the autumn will expose cocoons for the birds to dispose of. Thrips are more of a problem in hot, dry weather along with powdery mildew.

Powdery mildew, which is caused by a fungus (Erysiphe pisi), is normally encouraged by hot, dry weather and a lack of sufficient water – ensuring that your soil is well-prepared and well-irrigated can help to prevent the problem. Symptoms of infection are white powdery patches found on the foliage (both sides), although this is preceded by small, hard to see, yellow spots/blisters on the plant. Severe infection may result in distortion of the plant, although in peas this usually causes few problems as infection tends to occur towards the end of the cropping season. Spraying with a suitable fungicide (such as one containing carbendazim) can help to prevent/control the disease, although as with any edible crops if infection is mild then it may be better to ignore (or simply remove) the disfigurement. Infected plant parts should be destroyed as the spores of some powdery mildews may overwinter.

Harvest and Storage:
Peas should be harvested as soon as possible when ripe, as they can quickly become mealy (hard and lose their sweet taste). Although peas can be frozen, they are best when freshly harvested – pick them just before they are needed for cooking as they tend to lose their flavour quite quickly. It is worth remembering that the pods nearest the base of the plant will ripen first, with the rest following upwards – pick those at the bottom first. When you have harvested all the pods, cut off the foliage and dig the roots into the plot – as peas (like beans) are nitrogen-fixers and will help to improve the condition of the soil.

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Lettuce:

Introduction – Varieties:
The range of lettuces available seems almost infinite, with four main types and a multitude of varieties therein. The four main types are: round cabbage type (soft leaved or butterhead), curly crisp types, Cos, and open-hearted, cut leaved or loose leaf. If sufficient care is taken when selecting varieties to plant, then lettuce can be made available for harvest all year-round.

Cabbage-type lettuces are by far the most useful in providing a year-long succession of crops for harvest as, through various ‘tricks of the trade’, they can be sown throughout the year and harvested every month of the year. Sowing seed of a variety such as ‘Valdor/Dandy’ under polythene in October will give you lettuces to eat from January through until April. An indoor sowing of ‘Cobham Green’ mid January to February will produce lettuce for harvest in May-July; and an outdoor sowing of ‘Suzan’ throughout March-June will provide lettuces from June-September; and seed of a lettuce such as ‘Rachel’ sown in April will provide fresh lettuce for your table from October right through until December. All this within one particular type of lettuce, and of course the interest can be improved by growing different types such as Cos or loose-leaved.

When planting out seedlings of the same variety, planting out a proportion of them and keeping some back for planting out a week or two later will help to ensure a steady succession of crops.

Soil Preparation & Planting:
Soil preparation and providing the most suitable site for growth (especially during the colder months) is vital when planning a succession of lettuce. Crops which will be grown and harvested during the winter months need to be given the protection of cold-frames, polytunnels (see Diagram 6) or individual cloches. Care needs to be taken to prepare the soil adequately, ensuring that the pH and moisture level are as good as possible in order to help the plants along (lettuce prefer pH 6.8 for mineral soils and pH 6.0 in peat soils). Beware of growing lettuce in a site which has previously been home to chrysanthemums as this will increase the risk of root maggot.

Lettuce should be sown in rows, with approximately three lettuces per 1 metre row. It is also a good idea to choose a site which is not in full sun during the hottest parts of the day, lettuces have a tendency to bolt which is exacerbated by hot, dry conditions – keeping them well irrigated will help (and there are varieties which have some resistance to bolting), but it is as well to bear this in mind.

Table 1: A rough guide to successional sowing.

General Care:
If growing under ‘Dutch lights’ (a cold frame) for a spring harvest one needs to make sure that the glazed panels are lifted to provide ventilation when the weather is warm – removing the panels entirely and replacing them with horticultural fleece is also a viable option. Although feeding can be beneficial, beware of over-feeding the soil as this can encourage rot. Weed control and keeping the soil sufficiently irrigated can be dealt with together by applying a mulch or laying black plastic sheeting (with holes cut into it for the plants to grow through).

Harvest:
Lettuce (with the exception of those varieties grow for harvesting leaves as needed) should be harvested as soon as they are mature as they will readily bolt if left too long. Harvesting is best done in the morning and in cool weather, lift the lettuces with a trowel (roots and all) and then trim with a sharp knife. Do not cut the lettuce and then leave the remaining stump in the ground as this will attract the attention of pests as it starts to rot. Leaves should be harvested from ‘picking’ lettuces as and when needed – cut the outer leaves away from the plant with a sharp knife (cut as near to the base as possible) and new shoots should replace those which have been cut.

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Raspberries:

Preferred soil conditions/planting site:
The raspberry, Rubus idaeus, prefers a moist, reasonably light soil with a neutral pH. As canes are likely to be grown in the same position year after year (unless serious disease prompts a move in site), ensure that the soil is well-prepared with well-rotted manure. Full sun is not a necessity as raspberries will grow wild in forests where sunlight is patchy. When you have decided where your row will go, set a post firmly at each end between which should be strung wires to support the canes (wires should be approximately 60cm apart).

Planting:
Raspberry canes are usually bought as bare-root plants and are available for planting between March-October. As they are bare-root they need to be planted as soon as possible after receipt – they should be planted at approximately 40cm intervals along the row. After all the canes are in place, pruning them to about 20cm above soil-level (with a sloping cut just above a strong, healthy bud) will strengthen the plants.

General Care:
Summer-fruiting raspberries crop from the current years shoots from the previous years branches. During their first year one should aim to produce a healthy root system, sometimes at the expense of fruit. Generally, prune as soon as possible after fruiting to remove the growth from the previous year (making sure to remove any diseased or weak shoots) and then tie in the remaining shoots to provide them with support while they continue to grow.

Autumn fruiting varieties crop on branches grown in the current year – to prune remove all growth to about 20cm from ground level in February.

For both summer and autumn fruiting types, apply feed and/or mulch to the surface of the soil in February – the roots of raspberries are quite shallow so be wary of digging it in.

Pests and diseases:
Raspberries are prone to attack by a whole host of pests and diseases, some of which are: viruses (and aphids as carriers of viruses), cane blight, spur blight, botrytis (grey mould), raspberry beetle, caterpillars (of the raspberry moth), rust and cane midge. As such, especial care should be taken to select those varieties (as far possible) which show some resistance to certain diseases, and to take preventative measures against these problems. Some preventative measures are:- raking up any diseased leaves at the end of the harvest to prevent rust spores from persisting, cultivating the soil in winter to get rid of cane midge larvae, spraying in winter with tar oil to deal with over-wintering raspberry moth caterpillars and aphids, and cutting out any diseased canes.

Harvest:
Raspberries do not ripen all at once, so there should be enough for you to pick over several weeks. Although they don’t keep long, they do freeze well – freeze them whilst spread out in a single layer (to stop them sticking together), then when they have frozen they can be put into a container to save space.

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Tomatoes (from seed):

Introduction – The Basics
Good hygiene is essential when growing tomatoes, and starting with clean new (or sterilised) soil. This is important as tomatoes are susceptible to fungal infections such as buck eye rot and others. Choosing a suitable type (i.e. indeterminate, cordon) of tomato is also important when selecting seeds to grow, and choosing a variety which is both resistant to certain diseases and also have a nice flavour is another important consideration.

Propagation
Tomatoes may be propagated either with or without heat, although mid-winter sowings will require heat in order for germination and growth to be successful and guidelines and suggested temperatures are available for those who wish to start off their tomatoes during the cold winter months. On the whole, a temperature of around 20°C is suitable for the raising of tomatoes from seed towards the end of April, temperatures should be lowered to (and then maintained at) between 15-18°C later in the plants life span, with ventilation needed if temperatures rise to 23°C or above.

The germination period for tomato seeds is usually between 8-11 days (dependant on temperature and seed viability). If the intent is to grow a large number of plants then seed can be sown thinly in trays (cover only lightly with compost) and kept moist in an optimum temperature of around 18°C, seedlings should be pricked out when they have formed their first pair of true leaves. Alternatively, if only a small number of plants are required, sow either single seeds into cell-trays, Rootrainers or Jiffy pots, or a couple of seeds per 3 inch pot (with the idea being to remove the weaker seedling after germination).

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Tomatoes (from young plants):

Introduction – The Basics:
In order to best grow tomatoes outdoors, one needs to choose the site carefully – tomatoes will not cope with frost, so a warm, sheltered site is required. A wall or fence that faces south or southeast will provide the necessary shelter from the often cold north winds, and a site with this orientation also had the added benefit of the sunlight for the greatest proportion of the day.

Prepare the soil accordingly before planting out the young plants. Tomatoes thrive in well-cultivated soil, so the planting site should be dug over thoroughly in the process incorporating a goodly amount of organic matter (such as well-rotted manure). Throughout the growing season keeping the soil moist is of paramount importance in order to prevent blossom-end rot or splitting of the fruit (which is caused when the soil dries out) – as such one might consider incorporating water-retaining granules into the soil when digging in the organic matte. The use of a mulch on the surface of the soil is also something to be considered, as this will help to lessen the loss of water from the soil through evaporation; an added benefit of mulching is that it will help to stifle weed growth. If the tomatoes being grown are of a bush variety, then a synthetic mulch (i.e. plastic sheeting as opposed to wood chips) will provide the above benefits, plus helping to keep the fruits which are lowest on the plant from coming into direct contact with the soil and becoming muddied.

Once the plants have been hardened off and are ready to be planted out, at a spacing of 45cm apart with 75cm between the rows, further care is dependant (to some extent) on the type of tomato being grown.

Varieties:
Cordon varieties of tomato are grown on a single stem, and as such they need to be given adequate support, through staking with a bamboo cane. Conventionally, cordon tomatoes produce their fruit on four ‘trusses’. The term ‘truss’ refers to the sets of flowers which form on the plant just above a leaf joint (axil); a strong, healthy plant will usually produce trusses at approximately 30cm intervals up the main stem. So, a vigilant eye must be kept on the growth of the plants in order to stop them (by pinching out the top) when the fourth truss has set. This will encourage the plant to produce and ripen its fruit in ample time before the first cold of autumn sets in. One must also remember to pinch out any side-shoots which develop at the leaf axils as these would otherwise divert the plant’s energy from the production of fruit. Although it is common practice to leave only one main stem on a tomato plant, it is possible to allow a couple of very strong side-shoots to grow on and become additional main stems in order to increase the yield of the plant. A new variety ‘Sungella’ is a good cordon tomato to grow, with good-sized, orange-coloured fruits produced on long trusses.

‘Bush’ varieties can be further divided into two distinct categories, bushes which are 30-75cm, and creeping plants which are less than 27cm tall. The latter variety has the advantage of not requiring anything in the way of staking or stopping, but carries the disadvantage of being more difficult to harvest the fruits from. ‘Red Alert’ is a good bush variety, providing an early crop with a high yield.

The final variety is the hanging tomato – basically varieties whose characteristics lend themselves to being grown in hanging baskets (or, indeed, in window-boxes). Tomatoes grown in this way are usually small-fruited, and would be ideal grown near to the kitchen for ease of access when preparing salads. Good varieties of hanging tomato include ‘Balconi Red’ (one plant being sufficient for a 30cm hanging basket) and ‘Gartenperle’.

Feeding:
For all varieties, feeding is of utmost importance once the plants start to produce fruit (feeding prior to this can encourage more foliar growth at the expense of fruit). Potassium and nitrogen are the nutrients which tomatoes require for the best yield, these are best attained through applying a mixture comprising equal parts dried blood and sulphate of potash as a top dressing. Other forms of feed may be used, of particular convenience are those proprietary liquid feeds sold either ready mixed or only needing dilution prior to application. In addition to feeding, care must be taken to ensure that a regular supply of water is provided.

Pests and Diseases:
Throughout the growing season one should keep an eye out for pests and diseases which afflict the plants, and take suitable measures to control or eradicate them. Two pests which prey on tomatoes are aphids (greenfly and whitefly) and the western flower thrip. A proprietary pesticide containing pirimicarb will take care of aphids efficiently, or if you garden organically you could spray with a dilute solution of soapy water and consider companion planting (e.g. Tagetes) to attract more beneficial insects to deal with the aphids. Diseases that affect tomato plants are blight, blossom-end rot and grey mould. Blight (caused by a fungus called Phytophthora infestans) is a particular threat during extended periods of bad weather, causing damage to and eventually destroying the foliage of the plant – this can be controlled/prevented by spraying with an approved copper-based fungicide, or one containing mancozeb, every couple of weeks. Any part of the plant infected should be destroyed and not composted as the spores can overwinter. Grey mould starts by attacking any damaged areas of the plant, infection and spread of the disease can be prevented through the removal of any dying or infected foliage and fruit, and by ensuring that the plants are adequately spaced. Grey mould causes fruit drop. Blossom-end rot is a symptom of calcium deficiency, most often caused by a lack of water (insufficient or irregular watering) – this can be prevented through ensuring that the plants are watered adequately at regular intervals.

Harvest:
Fruits should be harvested when they are fully ripe, the colour will depend for the most part on the variety being grown (colours vary from shades of red through to yellow, and even green). At the end of the season, if there are fruits still remaining on the plants which have yet to ripen, one can pull up the plant in its entirety and hang it in a warm room – this will encourage the remaining fruit to ripen so that there is little waste.

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Melons:

In contrast to cucumbers, melons thrive in a constant temperature of around 27°C – this is lowered slightly when the fruits start to ripen. Humidity is quite important, as the high temperature and a dry atmosphere will encourage pests such as red spider mite. Traditionally gardeners would douse the floor of the melon house with water to keep the humidity at a suitable level. As with temperature, humidity levels should be lowered slightly after the fruit begin to ripen.
The other crucial difference in the cultivation of melons in comparison to cucumbers is pollination: melons require pollination in order to produce fertilised fruit, whereas the pollination/fertilisation of cucumbers should be avoided at all costs. Hand-pollination is often used, as this will allow a greater degree of control as regards yield. It has been suggested that as one male flower will pollinate four female flowers, hand-pollination take place when at least four flowers are open – however as female flowers are only receptive for one day it may well be prudent to pollinate as and when one sees an available flower. Female flowers can be recognised quite easily as (for both melons and cucumbers) they are borne singly and have an ovary (which looks like a miniature fruit) at the base of the flower; male flowers on both plants are borne in clusters (usually of three or five) and lack the distinctive ovary. [See Diagram 1: Male and Female Cucumber Flowers (which are similar to melon flowers)]

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Cucumbers:

Although germination of cucumbers takes place at the same temperature as for melons, a lower temperature range is required to keep the plants happy after propagation. The daytime temperature in the glasshouse should not reach above 24°C (if the temperature gauge indicates a higher temperature then ventilation should be given), and temperatures at night should not be allowed to drop below 17°C.

It is crucial to the production of palatable cucumbers (grown under glass) that pollination does not occur. When the fruits are fertilised their taste becomes bitter (this is not applicable to outdoor, or ridge, cucumbers, which require fertilisation). As such, care should be taken to exclude pollinating insects from the glasshouse – this can be managed through the use of fine nylon netting fixed over any ventilation apertures, and of course through being careful when entering the glasshouse not to bring any insects in with you! Another measure which is often employed in the prevention of pollination is to remove any male flowers found on the plants – these days some F1 hybrids, such as ‘Feminex’, are available which produce only (or predominantly) female flowers.

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