At this time of the year most gardeners relax by the fireside and peruse seed catalogues, gardening books and make plans for the new season. Nevertheless, ignoring the garden in the midst of winter can be a costly mistake, where plants can be lost in very sever frosts and winter gales or die smothered by rotting leaves and debris.
Take advantage of any mild spells, especially during the holidays, to check the condition of plants and protect them where necessary. Continue outdoor garden tasks such as winter digging and knocking snow off evergreen trees and shrubs.
Check that gutters and drains are not blocked by fallen leaves. Don't forget to clear ice from garden ponds as it can deprive the fish of vital oxygen.
During December the greenhouse can become stagnant, and cold air can quickly lead to a build-up of fungal diseases, so it is better to ventilate as the weather permits so that plants have fresh air, so long as it is not frosty.
Don't forget to order those seed catalogues early in December so you can browse through them during the Christmas holidays.
Garden soil that needs improving should be tackled now. Garden soil is a complicated mixture of rock particles and organic material, together with water, air and nutrients. The major soil types are chalky, peaty, sandy, clay or loam. In addition soil can either be acid or alkaline. All of these properties will affect the type of plants that will survive or thrive in your garden. The ideal soil is a rich, free draining, dark loam but whatever your soil type it can be improved as follows:
If your soil is very limey (alkaline), iron and other trace elements can become 'locked' in the soil. Digging in a peat substitute or lime free compost and applying flowers of sulphur or sequestrene (chelate of iron) can help. If you want to grow acid loving plants you can make a raised bed and fill it with lime free compost or grow acid loving plants like rhododendrons and azaleas in tubs and containers.
Acid soil can be made more alkaline by adding a dressing of hydrated lime, ground chalk or limestone. For sandy soils, use 225 g per sq m (8 oz per sq yd), double this amount for heavier soils.
Clay soil is heavy and tough to dig over at any time of year but especially in summer when it can dry rock hard and in wet weather it can become sticky and waterlogged. Also because it holds water, it tends to be cold and slow to warm up in early spring. However, it can be very nutrient rich. It is best to dig clay soils over in the winter, so sharp frosts can break down the clods. You also need to dig in as much organic matter as possible - aim for two bucketsful per sq m (sq yd) and leave at least a month before adding lime.
Sand does not retain water, and vital nutrients get quickly washed through to the subsoil. It is much improved by the addition of organic matter. Besides providing nutrients to the plants, it helps retain moisture. Sandy soil is often acid, in which case it will benefit from the addition of lime, as well as organic matter.
Chalk-based soils are generally light and shallow, don't hold water well and are extremely alkaline. You can increase the acidity by regular applications of flowers of sulphur or sequestrene. Alternatively, you can simply grow some of the many lime-loving plants. Regular applications of organic matter, will also allow a wider range of plants to be grown.
December is the best time to clean your garden tools and keep them in good order, while they are less frequently used. Secateurs, saws and pruning knives can be repaired, oiled and sharpened. Spades and hoes will need sharpening and cleaning. The tines of forks and rakes may need straightening.
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UK gardens open in December include:
Glasshouses with many tender plants. The arboretum looks especially good in the autumn, with beautiful trees in a parkland setting.
Ten landscaped glasshouses with a huge range of exotic
plants. World-famous rock garden is particularly good in spring/early summer.
Woodland garden and arboretum.
Landscaped with many attractive features and themed areas including alpines, heathers, roses, fruit and
Headquarters of the RHS. Formal water garden, glasshouses,
huge rock garden, herbaceous borders, alpine houses, rose gardens,
demonstration gardens, woodland and wild areas.