Feeding Garden Plants – Making Compost

Feeding your Garden Plants

In order to grow flowers well the first essential is to look after your soil. Whatever your soil, be it light sandy or heavy clay, the secret of improving it is the addition of decayed organic matter rich in humus. Curiously enough, decayed organic matter is highly beneficial to diametrically opposed types of soil: to a thin, sandy soil it will act like a sponge and make it much more moisture-retentive, while it will lighten, warm and help break up a soil of heavy clay. It will greatly improve the structure of both, so that the multitude of plant roots, on their busy search for water and plant nutrients, can move easily through the soil.

The garden store cupboard

Feeding garden plants - making compost No amount of later cultivation will take the place of initial thorough digging and preparation of the soil with the liberal addition of compost or well-rotted manure. But with a well-stocked garden store cupboard you can offer your plants generous helpings of whatever they need when planting, feeding or top-dressing them.

Compost, manure or leafmould — individually or in any combination — can be mixed with the soil in the bottom of planting holes (using, say, half to one bucketful per herbaceous plant and two to four bucketfuls or more for a tree or shrub).

The compost heap

The nerve centre of the garden, the compost heap is a wonderful source of organic matter rich in humus. The breaking down of all your garden rubbish and vegetable trimmings from the kitchen within a well-made compost heap, converts them into a dark, crumbly substance, with a sweet and settled smell. When vegetable matter decomposes it heats up, thus encouraging all sorts of bacteria and microscopic fungi to multiply at a fast rate, and get on with their business of transforming the waste into compost. Grass mowings and green, leafy weeds heat up quickly, while woody stems of herbaceous plants are much slower. The idea is to achieve a balance between the two, using the coarser material, chopped up herbaceous stems and so on, interspersed with softer, leafy matter. Too thick a layer of grass mowings, for example, will turn into a slimy mess and too thick a layer of woody material might not heat up properly. Soil, attached to weeds and discarded plants, and path sweepings all go into the mixture.

You can use a proprietary compost activator (more likely to be necessary in autumn and winter) or cover each 25cm (10in) layer of refuse with a thin layer of fresh farmyard manure. The finished heap should be capped with a 2.5cm (1in) layer of soil and a sheet of polythene for insulation. Do not put on autumn leaves (these are better kept separately to make leafmould, as they are slow to rot down), or grass cuttings when you have just used a lawn weedkiller, or material like chicken bones from the kitchen — there is nothing a mother rat likes more than a nice warm compost heap.

Making compost

Ideally, you should have two compost bins side by side, made out of slatted wood, and about 120cm (4ft) square. The slats on the front of each bin should be removable to allow access. As the first becomes full up, you can turn the heap into the second bin, an action which further aids the rotting process. Compost bins can also be made out of bricks or concrete blocks, leaving plenty of gaps for aeration. Proprietary plastic compost bins with holes in the sides are good for small gardens.

Mature compost is welcomed by just about any plant, with very few exceptions, one of these being New Zealand plants which resent rich feeding. It may be used for the initial digging, for working into the bottom of planting holes, for mulching and, when well-matured, small quantities may be required in potting mixtures. If you garden on limy soil, be wary about using garden compost for ericaceous plants, since it might contain some lime, introduced by weeds with garden soil on their roots.

Farmyard manure

Thoroughly rotted farmyard manure is one of the best sorts of nourishment for the soil. It is worth every effort to locate, but never refuse a fresh load — just store the heap for a few months until it matures, under a sheet of polythene to prevent the goodness leaching away. It can be used for incorporating during the initial digging, and for preparing the planting holes of any plants, especially roses, delphiniums, peonies, dahlias and clematis.


Leafmould is the flaky, brown, crumbly material found in woods, just under the layer of leaves that fell the previous autumn. You can make leafmould from your own autumn leaves by simply stacking them in a wire-netting enclosure; the best leafmould comes from oak and beech leaves. Never put in plane or sycamore leaves, as they take too long to rot, or leathery evergreens like yew or holly. Pine needles should also be avoided as they take too long to decay and the resulting mould is too acid. Rich in humus, leafmould is the perfect soil-enricher for woodland plants; it can be worked in as you plant or used as a mulch. If it is in short supply, save it for putting beneath your trilliums and snowdrops.

Leafmould is also one of the ingredients in a general potting mixture for alpines (one third each of leafmould, loam and sharp grit). For use in potting mixtures it should crumble up nicely when rubbed between your hands, or it can be rubbed through a coarse garden sieve. As a mulch it can be used as it is.

General fertilizer

While the importance of adding organic matter to your soil cannot be over-emphasized, your plants are going to need an extra tonic in the form of a general fertilizer. This contains a balanced combination of nitrogen, phosphorus and potassium, three vital elements for healthy plant growth. Broadly speaking, nitrogen builds up leafy tissue — the leaves, stems and shoots — phosphorus encourages root growth, and potassium develops the flowers and fruit. On a packet of fertilizer these are indicated as N, P and K respectively.

A general fertilizer is used when planting and can be applied to the flower beds in spring, working it in lightly with a fork; it can also be scattered around any plant that does not seem to be doing well. Never exceed the amount recommended on the package.


Made from ground-up bones, bonemeal is a slow-acting fertilizer. Applied in autumn or spring, it is excellent for putting in the bottom of the planting hole for trees, shrubs, roses, bulbs and herbaceous plants. Coarsely ground bonemeal is particularly useful for bulbs, which in general dislike farmyard manure or bulky organic matter, and should be either added when planting them or mixed into the surrounding soil as they appear in spring. It can be applied at up to 225g (8oz) per square metre. Finely ground bonemeal (apply at 75-100g/3 —4oz per square metre) is faster acting.

Liquid fertilizer and foliar feeds

Liquid fertilizers and foliar feeds are good, fast pick-me-ups for use on plants during summer, particularly for plants in containers, where there is a restricted root run, and for those in soilless potting composts, where plant foods are rapidly used up.

Sand and grit

There is no food value in sand, but it is essential for assisting drainage either in the open ground or as a constituent of potting composts and cutting mixtures. On no account should builder’s sand be used. Horticultural sand is clean and free of silt: when you scrunch it in your hand it should feel sharp. It is also useful for putting round bulbs such as crown imperials (Fritillaria imperialis) and lilies to stop waterlogging and to deter slugs.

Grit comprises little chippings of stone which should feel sharp when you take a handful. It is invaluable for working into heavy soil to lighten it and assist drainage, and as a constituent of potting composts for alpines and bulbs, as well as for adding to the soil when making a raised bed.


Rotted compost, manure and leafmould all make ideal material for mulching, as do bark chippings. A layer of any of these, about 10cm (4in) deep, applied in spring or autumn when the soil is damp but not cold, is an excellent way both of keeping weeds from germinating and of conserving moisture round the plants’ roots.

27. December 2010 by admin
Categories: Compost and Manures, Garden Care | Tags: , , | Comments Off on Feeding Garden Plants – Making Compost


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