HedgeWytch's Healing Garden: Gardening Information

Hoeing:

Hoeing is an action performed to cut off weeds at the surface of the soil, thereby not disturbing the roots of cultivated plants, it is also used to cultivate soil and help bring it to a fine tilth. There are several different types of hoe:

Although draw hoes can be used for weeding (in particular dealing with large weeds using a backwards chopping motion), they are best used for earthing up soil and drawing seed drills. An onion hoe is basically a smaller-bladed draw hoe with a short handle, designed to be used on your hands and knees between narrow rows of plants (not just onions).

Dutch, or push, hoes are perhaps the best at tackling weeds, the thin blade needs to be kept sharpened in order for it to remain efficient.

Two-way hoes are used with a push-pull motion and have a double-edged blade.

Wheel hoes are very useful labour saving devices in large vegetable gardens, as you can fit an appropriate ‘head’ for your needs and simply push the hoe along.

The claw hoe, also known as a Canterbury hoe, is used to cultivate soil.

Rotary hoes are more the province of farmers or those with large gardens, they work mechanically (driven by a motor/engine) and really churn up the soil, which function can also be used to work in organic matter or seeds.

Stem Cuttings:

In a situation where a plant is considered ‘difficult’ to root there are several things which may be done to encourage the formation of roots. The cells at the base of the cutting have to absorb water (to keep the cutting alive), heal the cut (forming callous tissue), and form roots – all this can be encouraged as follows:
When taking a cutting, try to ensure that it is of a suitable size – too small and it might not succeed, too large and the roots, when they form, will not be sufficient to support it. Cutting material should also be as healthy and fresh as possible – wilted cuttings are not likely to do well as their internal reserve of water is already depleted (aim for maximum turgidity).

Cuttings may be treated with fungicides and/or rooting hormones prior to insertion into the chosen rooting media. These provide obvious benefits: fungicides will kill off any (fungal) diseases which may already be present on the cutting material, as well as preventing further infection. The addition of rooting hormones will stimulate the cutting to callous and form roots by ‘boosting’ meristematic cells and thus increasing the rate of cell division.

Providing gentle, and constant, heat to the base of the cutting may also aid rooting as this can stimulate cell division. Be wary, though, of providing too warm an air temperature as this can cause the cutting to wilt.

Provision of water is a tricky one. The cutting best absorbs water when it’s provided as a thin film – many gardeners stand cuttings in water, which isn’t necessarily ideal. Trial, error and experience are perhaps the best indicators of how much water should be provided to cuttings.

The rooting media is another important choice. Regular garden soil is generally unsuitable, and some plants have specific requirements when cuttings are being taken. An open, well draining (yet capable of providing sufficient water) media is best. The media chosen should be low in nutrients, although when the cutting has rooted it can be transferred to a more substantial mix which is better able to support the new root system.

Propagating Herbaceous Plants:

Seed – propagating herbaceous perennials from seed is a cheap and satisfying way to fill your garden with colour. Although they are unlikely to be of flowering size in their first year (unless sown in midwinter and brought on under glass before planting out) they will repay the care and attention for many years, providing you with a wonderful display. Seeds can be sown in pots or trays, in a proprietary seed compost. Sow as thinly as possible (mixing any fine seeds with sand in order to make sowing easier) and remember to thin out the seedlings to prevent overcrowding once they’ve appeared. Keep moist and be vigilant for any signs of fungal diseases (such as damping off), although good hygiene and a sufficient flow of air around the seedlings should minimise the risks. As the plants develop, pot on into slightly larger pots to encourage vigorous and healthy growth prior to planting out. Plants may require hardening off before being planted into their flowering positions outdoors.

Division – herbaceous perennials are most often propagated by division. Clumps with fibrous roots (e.g. Melissa officinalis or Achillea millefolium) are lifted and, usually (as it is an easy method and retains much of the fibrous roots), divided by placing two garden forks back-to-back in the clump and then prised apart. These halves can then be further divided. Rhizomatous roots (e.g. Hosta) can be divided similarly using a knife or (if it’s a particularly vigorous clump) the blade of a spade. As a general rule of thumb, divide autumn-flowering plants in the spring, and spring and summer flowering plants in the autumn.

Softwood stem cuttings - Cuttings should be made in mid-summer from spring blooming plants like Phlox and in late spring from summer and autumn flowering plants like Sedum. Take cuttings of 2 to 3 inches in length in early or mid-morning. Dip these in a root-promoting hormone and plant into rooting medium. The cuttings may be kept out-of-doors in a shady, protected spot where they can be kept moist. After top growth extends several inches, the plants can be set into permanent garden locations.

Root cuttings – some herbaceous perennials, such as eryngium and verbascum, can be propagated through root cuttings. These are taken during the plant’s dormant phase (usually in the winter). Cut the roots into sections about 5cm long using a sharp (and clean) knife. Plant them (making sure to plant them the right way up) vertically (although thinner roots can be laid horizontally and covered with their own depth of soil) into a well-drained (50:50 compost and grit or sand) potting media and keep under glass (in a shed or greenhouse) until they root. You will notice top growth appearing first, but check that there is sufficient root growth to support the plant before planting out/potting on.

Potassium Deficiency:

The first sign, which is very eye-catching, of potash deficiency in hardy fruits is leaf scorch (usually in the older leaves first) – this describes a scorched (browned) effect around the edges of the leaves (see Diagram 1) – often accompanied by chlorosis (yellowing) of the leaves, and in severe cases can progress into necrosis (necrosis means death of living cells) of the tissues between the main leaf veins. This occurs because potassium is responsible for, among other things, the balance of water within the tissues of the plant.

Severe potassium deficiency will also lead to dieback of young shoots, or a failure to produce any new growth – it is also possible for entire branches to die back, although this would likely indicate a weak or old tree in conjunction with an unusually severe potash deficiency.

As potassium is responsible for increasing the quality of fruits, stunted fruits may arise, and as potash aids resistance to disease it is not unlikely that the plant may prove more susceptible to infection by other diseases. Potash also encourages root growth and strength, so a lack of potash will lead to a smaller and weaker root system which may succumb to rot.

Light, sandy soils are likely to be deficient in potassium – which likelihood is increased if the land is in an area of high rainfall. This is because light, sandy soils are prone to leaching, where the nutrients are washed through by water. Where an area has been used for crops continually then a potassium deficiency is also probable, although if the soil has not been ‘fed’ throughout an extended/uninterrupted period of cropping then a deficiency in several nutrients is likely.

The best form of potassium fertiliser to apply is probably potassium sulphate (K2SO4), as it contains a large proportion of potassium (50% K2O) compared to potassium nitrate (46% K2O) or monopotassium sulphate (34% K2O). This may be applied as a top dressing in the spring – applying it prior to the winter would mean that much of what has been added will be leached away by the winter rains. A foliar feed (where the fertiliser is sprayed onto the leaves) may also be used, which has the added benefit of being taken up by the plant and used almost straight away. This latter method has the disadvantage of needing to be applied on a regular basis (as the fertiliser, in its liquid form, will not remain either on the leaves or in the soil for very long), and also that if applied in strong sunlight it may cause scorching to the leaves (which may cause problems in the summer).

Humus:

Humus is colloidal organic matter which is, usually, of a dark-brown to black colour. Humus is beneficial to soil in that it improves the friability of the soil, and helps it to retain nutrients and water – in addition to which, the dark colour of this organic matter enables the sunlight to warm it faster (in comparison with a light-coloured soil). From a more scientific angle, humus also increases the cation exchange capacity of the soil – in layman’s terms this means that the plants are able to take up more nutrients from the soil. Derived from all manner of organic matter, humus has an higher carbon content, and a lower nitrogen content, than the material it originally came from.
Humus, the end product of the decomposition of organic matter, is essential to healthy plant growth. This unprepossessing, dark brown substance can hold nutrients and water and improves the structure of the soil. A colloidal substance, humus improves the aggregation and workability of the soil, and its high cation exchange enables plants to take-up more nutrients than they would otherwise.

Trace Elements:

Trace elements (or micronutrients as they are sometimes known) are, as with major nutrients, essential to plant growth and health – but are required in much smaller quantities. The trace elements are:

Iron – a deficiency of iron is usually noticeable by the occurrence of lime-induced chlorosis (when the foliage appears yellow). As the name suggests, this is caused by a high level of lime in the soil, which ‘locks up’ the iron within the soil and makes it unavailable to plants. Iron chelate may be applied to remedy the problem.

Boron – Boron is required for carbohydrate metabolism, sugar transport, lignification, respiration, seed and cell wall formation, and pollen viability. Boron deficiency causes a breakdown of the growing tip tissues, or a shortening of the terminal growth. Boron deficiency is not usually a problem when growing fruits in the UK, although when growing vegetables one should be aware that brassicas may suffer as a deficiency may become a problem in soil which has been limed. Treatment of boron deficiency is usually through the use of borax although specialist advice should be sought before use.

Copper – All plants require copper for plant growth and for the activation of many necessary enzymes – a lack of copper interferes with protein synthesis. Although it is uncommon for a copper deficiency to be a problem, it can occur, especially on sandy soils (which are notoriously poor at holding nutrients). Symptoms include die back of shoots, and this may be remedied by the foliar application of copper sulphate (0.22kg in 455 litres of water is sufficient).

Zinc – This element is essential as it regulates plant growth, and is necessary for chlorophyll synthesis and carbohydrate formation. A deficiency will manifest in young leaves first. As with boron, a deficiency in zinc is rare but if it occurs it may be identified by the formation of rosettes of small leaves on the terminal growths.

Manganese - although it should not be confused with the macronutrient magnesium, manganese does perform some of the same tasks – namely the activation of certain phosphate-transferring enzymes, which affect metabolic processes. It should be noted that an excess of manganese can induce iron-deficiency. The main symptom of manganese deficiency is interveinal chlorosis, although certain plants may suffer from reduced leaf size or speckling on the foliage. Deficiency is usually to be found on slightly acid or alkaline soils – although acid soils which have been limed are more prone to exhibit deficiency than soils which are naturally neutral or alkaline. Manganese sulphate may be applied to the foliage as a solution (1.4kg in 455 litres of water, 2-3 applications may be needed) to remedy the problem.

Molybdenum – Trace amounts of molybdenum (which is a transition metal) are required for all known forms of life; in plants it plays a role in the pathways of nitrogen fixation and nitrate reduction – deficiencies are most common in acid soils. Sodium molybdate may be applied as a soil dressing (27g per hectare) or foliage spray (113gms in 45 litres of water) to remedy the problem.

Photosynthesis:

Photosynthesis (sometimes known as ‘carbon assimilation’) is the process by which plants produce glucose and oxygen using the energy from sunlight in the presence of chlorophyll. The most succinct description is that it is the synthesis of compounds (within plants) with the aid of radiant energy.
carbon dioxide + water = glucose + water + oxygen

Simply put, plants use the chlorophyll in their leaves to convert carbon dioxide (CO2) and water (H2O) into sugar (specifically, glucose C6H12O6). The by-products of this process are water and oxygen (O2).

Chlorophyll is contained in cells called choloroplasts – it is a catalyst in the process of photosynthesis, it aids the process but remains unchanged within itself. It is chlorophyll that gives plants their green colouration. In the case of plants with variegated leaves, chloroplast is still only contained within the green areas of the leaf – so although one might have a plant with extremely pale variegation, and which has some completely white/cream leaves (e.g. Mentha suaveolens variegata – variegated pineapple mint), it is not possible for the plant to ever have only white/cream leaves as the plant would then be unable to synthesise food. Similarly if plants with variegation are planted in a very shady place may lose their variegation (‘revert’) as their leaves struggle to absorb enough light to photosynthesise – their leaves revert to green to maximise the amount of leaf area which is capable of photosynthesis.

Photosynthesis only occurs during daylight hours, when the sunlight provides enough energy to power the process. Special lamps, which mimic the light frequencies of true sunlight, may be used to encourage photosynthesis indoors/at night.

It immediately becomes apparent that plants, therefore, cannot produce food for themselves at night or when the amount of sunlight is otherwise lessened (e.g. cloudy days) – as living plants require energy (and therefore food) all the time, this might appear to be a problem.

However, plants have the ability to produce food (glucose) in great amounts when the energy source is strong (i.e. during the daytime) and then store it for later use (i.e. at night, or when the sky is overcast). Excess glucose is converted into starch, which can then be stored for long periods of time, sometimes in leaves but most often in the roots. When the plant requires more energy, especially in the absence of sunlight, the starch is converted back into sugars.

Transpiration:

Transpiration is the term given to the loss of water from a plant through evaporation. The water is mainly lost through the stomata (surface openings, or pores, on the lower leaf surface), although some is lost through the lenticels (pores in the stem).
The main purpose served by transpiration is:-

Supply of water – when water leaves the plant through evaporation a transpiration stream is established which induces movement of water up the stem, and the absorption of water (by the roots) from the soil. The transpiration stream is also responsible for the drawing of minerals into the plant. However, if the rate of transpiration is very high (due to climatic/environmental factors) then the rate of uptake (of water) may not be able to keep pace – in such a situation the plant starts to wilt.

Transpiration is usually a passive process, meaning that it is controlled largely by the atmosphere – however, it is worth noting that some plants do have the ability to control the opening and closing of their stomata. The rate of transpiration can be affected by light intensity, temperature, humidity, and wind

Light – this stimulates the stomata to open, thus allowing gas exchange for photosynthesis, and as a result this also increases the rate of transpiration. As mentioned previously, if the uptake of water by the roots cannot keep up with the evaporation of water through the stomata then the plant will wilt as a result.

Temperature – the higher the temperature, the higher the rate of evaporation of water. If the temperature is high and the atmosphere is ‘dry’ (i.e. the humidity is low) then the rate of transpiration is further increased.

Humidity – is the degree of moisture contained in the air. A high humidity therefore means a higher water potential in the air, which means a lower water potential gradient between the leaf and the air – consequently the rate of evaporation is less.

Wind – the action of wind moving moisture-laden air from around the plant and subsequently replacing it with drier air increases the water potential gradient and increases transpiration.