Mulch is generally used at the beginning of the season but there is no hard and fast rules so even if the season is well under way, it's still not too late to improve the soil with organic matter. Its important to make sure that the garden will perform well right through the season. In hot locations just a 4-inch (10cm) layer of mulch drops the soil temperature from 105 o to 80 o F. At the same time, it contributes organic matter and nutrients to the soil as it decomposes. Regardless of where you garden, you can still improve soil even once you're growing in it.

Organic Mulches:

There are so many ideas for the best material with which to mulch; one that is particularly effective is kelp meal. Kelp or seaweed is a great source of trace minerals and growth elements. Just apply 1 pound per 100 square feet at any time during the growing season. Adding seaweed triggers an increase in microbial activity and fuels the decay cycle of organic matter in the soil.

Some of the most commonly used organic mulching materials are manures; bark chips, sawdust, grass clippings, leaves, and newspapers (shredded or in layers). Organic mulches allow some flexibility in fertilizing and watering since they can be raked back from the plants. They should normally be applied uniformly 2 or 3-inch (5cm-7.5cm) deep around the base of the vegetable plant.

Inorganic Mulches:

Black plastic is the most frequently used inorganic mulch. Clear plastic is of little use, as it does not exclude the light that aids weeds seeds to germinate. Gardeners should make sure there is adequate moisture in the soil before any mulch is applied. There are also several durable weed fabrics that are very effective in weed suppression. The decision of whether to use organic or inorganic mulch really depends on the season of the year and what the gardener is trying to accomplish. Organic mulches should be applied after the soil temperature has warmed in the spring. If applied to cold soils, the soil will warm slowly and the growth rate of most vegetables will be reduced. Inorganic mulches can increase the soil temperature by at least 6 to 80F. therefore, their greatest value is early in the growing season when soils are naturally cool.

Leaf Mould:

Even if you don't have a compost bin you can still make compost from the fallen leaves. Simply collect the leaves and put them into a black plastic sack, place them somewhere out of sight in the garden and forget about them until later the following year, when you will have some rich compost to spread around the garden.

It takes at least a year to compost down the leaves, depending on leaf-type: beech or oak leaves decompose readily, but waxy leaves take much longer. (Sycamore and London Plane in particular take years to rot down) Also warm, wet, weather conditions promote faster leaf decomposition.

Once fully decayed, there should be no whole leaves present in the leaf mould. If it contains debris such as twigs, it should be put through a coarse sieve. The leaf mould can be added to potting compost (1 part leaf mould to 4 parts potting compost), or used liberally in the garden as plant mulch, or dug in to improve soil structure.