Vegetable Gardening in Late Winter

Sprouting

Maincrop varieties of potatoes can be put to sprout in late winter, in the same way as the earlies were. It is still possible to start the earlies off and get the crop at a reasonable time, provided you do it as early this month as possible.

Pruning

Raspberries should have the tips of the canes cut off now. They may have died back or been broken during the winter; moreover, shortening the very long canes of the modern varieties makes picking more manageable and encourages the plants to produce more fruiting laterals.

Liming

This should be dealt with quickly, as the time for applying fertilizers is approaching; as with manures, lime can react with certain fertilizers so that plant foods are lost, particularly those such as sulphate of ammonia, superphosphate and basic slag. To be on the safe side, never apply lime directly before or after putting on a fertilizer.

Fertilizing

As many plants will soon be starting to grow in earnest and as you will be sowing and planting new crops during the next two seasons, late winter is a good time to put on any mineral plant foods that you may think necessary. There will then be time for them to be dissolved in the soil moisture and become part of the soil complex; they will undergo various changes under the influence of the soil constituents, both living and inert, which will ensure that plant roots can absorb them, along with the soil water. Plants can only ‘drink’ the mineral nutrients from the soil; the particles must be dissolved in water before the plant can make use of them via the roots.

Of course, plants feed in other ways; as a result of the process known as photosynthesis, the green parts of the plant, especially the leaves, make (or synthesize), in the presence of light (photo = light), sugar and oxygen from the water and carbon dioxide of the air; sugar is then turned into starch and stored in this form. This is a very simplified version of the way plants feed and live but it is worth remembering that they need other foods than mineral nutrients and they obtain some of these from the air and rain.

Fertilizers and the soil are the main sources of supply of mineral nutrients; plants must have, in particular, nitrogen (N), phosphorus (P) and potassium (K), and in general these three must be provided in larger quantities than other minerals. Calcium, magnesium and sulphur are needed in moderate amounts, comparatively speaking, and there are a good number of nutrients or elements such as iron, manganese and boron which need only be provided in tiny quantities. These are called ‘trace’ elements. Modern fertilizers may contain mostly one element in a usable form – these are sometimes called ‘straights’ – for instance, sulphate of ammonia, or they may contain several (the compound Jertilizers), when N, P and K (and other nutrients) will be contained in them in varying proportions. Whatever type of fertilizer it is, there will be an analysis on the container which shows the percentage of the nutrient or nutrients in the fertilizer. Sulphate of ammonia is usually standardized at 20-21% N; a compound fertilizer will show an analysis of, for example, 6%, N, 9 per cent P205, and 12 per cent K20. In the case of phosphorus and potassium, for technical reasons, their content is expressed in terms of the phosphoric acid and potash content, rather than the pure element. None of them in fact is present in element form – nitrogen is there as a compound chemical substance, not as nitrogen gas – but the percentage given is a guarantee of the quantity of the nutrient content and the amount of fertilizer to be applied can be based on these figures.

The three major plant nutrients, N, P and K, have varying functions. Nitrogen affects the growth of leaves and stems, and ensures a good green colour and strong, vigorous development. Lack of it results in yellow or pale green leaves and stunted, slow-growing plants. Phosphorus affects root growth and is especially important for the roots of seedlings and young plants. Potassium is associated with the maturity of the plant: flowering, fruiting, development of seeds and colouring. Lack of phosphorus is not easily detected, though short, rather ‘hard’ plants, with purplish tints to the leaves, are some of the more obvious symptoms. Lack of potash will be obvious in poor fruiting, reddish or brown leaf edges, small and few flowers and little formation of seed.

These major plant foods also affect other processes in the plant and react with one another according to how much of each is absorbed. Trace and minor elements have various jobs to do as well, so the business of plant feeding is a complicated one. Adding fertilizers to the soil needs to be done warily, never in larger quantities than advised by the manufacturers and, if possible, according to the results of a soil analysis, which can be done with a soil-testing kit, or by a professional adviser.

However, if neither of these is available, provided you have used organic matter earlier and you are careful with quantities, you should not do any damage. The organic matter will act as a buffer if too much fertilizer is given and as you build up the soil fertility with it, you will be able to do with less and less fertilizer. Eventually, there may not be a need to add any at all.

When you do apply fertilizers, sprinkle them evenly over the soil surface in exactly the quantities advised, about ten to fourteen days in advance of sowing or planting and mix them into the top few centimetres (inches) with a fork. The soft fruits can be fed towards the end of late winter, if not treated the previous late summer; use a compound fertilizer with more potash in it than nitrogen or phosphorus, since they are fruiting plants. Asparagus and Jerusalem artichoke-can be given potash, preferably as wood ash, at the rate of 120g per sq m (4oz per sq yd) to established asparagus and rather more to the artichokes.

Bulking the fertilizers with coarse sand is one way of getting them spread evenly, or you can mix them with sieved soil. It is usually simplest to give a compound fertilizer, though if a crop has a particularly heavy demand for one nutrient, a straight can be used instead. In general the leafy vegetables will need more nitrogen; the roots, tubers and bulbs, as well as the fruiting vegetables need potash and all when young need phosphorus. Note that marrows, including courgettes, need nitrogen, rather than potash, although they are a fruiting vegetable.

Cloching

If you want to bring on strawberries early, covering them with cloches now will give fruit late in spring, earlier in warm gardens. Clear the plants of weeds and debris first, fertilize if necessary, and then cover. Straw will not be necessary as the berries will keep clean when protected. Other crops may begin to grow again; clean up these also and clear the cloche itself of mud and debris.

Protecting

Safeguards against birds and cold will still be very necessary, in particular for brassicas, shallots, gooseberries and currants (birds) and stored root crops, vegetables under cloches and young plants in the greenhouse (cold).

Stored crops

Continue routine inspections of these and increase the frequency of inspection, as all crops will be ageing and will rot more quickly and have less resistance to infection.

More on the Kitchen Garden in Late Winter …

29. August 2011 by admin
Categories: Kitchen Garden, Organics | Tags: , | Comments Off on Vegetable Gardening in Late Winter

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