The main manures for fruits contain nitrogen, phosphate and potash. Potash is of outstanding importance for all fruits, phosphates are not so important for the tree fruits and the needs for nitrogen vary. For example, plums and black currants benefit from heavy dressings of nitrogen, but generous nitrogenous manuring for apples, raspberries and strawberries may make the plants over-vegetative and reduce yield and fruit quality.

A balance must be kept between shoot growth and fruiting, with the aim of obtaining heavy crops of good quality for successive years. This can only be achieved by careful manuring, combined with other management practices, and in particular by the prevention of mineral deficiencies and excesses.

No fruits are real lime-loving plants, not even the stone fruits. Most prefer slightly acid soil conditions, or soils with only small supplies of free lime in them, whilst some fruits will grow well on strongly acid soils provided they are well manured. The great danger from overtiming arises in the fact that fruit crops are very susceptible to deficiencies of the so-called trace elements, particularly iron and manganese, and in a soil of high lime content these two elements may become unavailable to the plant.

A first principle in growing fruits should be to avoid highly calcareous soils and to be sparing in applying lime. Lime should only be applied if the soil is very acid.

The second point to stress is the importance of organic matter in fruit soils. Fruit plants must have a free-rooting medium for healthy growth and longevity, and this can be assured only by maintaining a good content of organic matter. For tree fruits such as apples and pears, this may be best achieved by growing the trees in grass after the first 3 or 4 years in clean cultivation, or by dressings of bulky composts or manures used as surface mulches. The grass and other organic materials must be kept clear of the tree trunk. For soft fruits the usual method is to dig in bulky manures or compost before planting.

It is usually necessary to use concentrated organic manures or inorganic fertilisers in addition to bulky manures to supply the right amount of nutrients needed. Any of the usual manures and fertilisers used for other crops are suitable, though a few precautions are necessary in some cases to avoid injury. All chloride-containing fertilisers, such as muriate of potash, should be used with caution, or not at all, on soft fruits, particularly red currants. Manures and fertilisers should be applied to the soil, and late winter and early spring – February and March – are the best times to apply them.

Excessive manuring, especially with nitrogen, is shown by over-vigorous growth, large dark green leaves, poor fruiting or large, poor-quality fruits.

The types of soil which suit individual fruits are referred to in the text; where the soil is not of a type likely to be suitable, efforts should be made to improve it when the ground is first dug and prepared, but no manure should be in contact with the roots at planting.

Digging one spit deep. This consists of breaking up the soil to the depth of a spade or a fork. A trench is taken out and the soil from the next strip is turned over into the trench.

If manure is to be applied it is a good plan to spread it over the ground to be dug to ensure even distribution, leaving the breadth of the first spade-cut clear of manure. When the strip has been dug and the soil removed, the manure from the next strip to the width of a spade should be placed in the trench, laying it on the sloping surface. Then the next strip of soil should be turned over into the trench, burying the manure, which is evenly distributed in the soil from the bottom of the trench almost to the surface.

Double-digging cultivated ground. Divide the plot into two, and mark out the boundary and dividing lines with a spade; then take out a trench, 2 feet (60 cm.) wide, and with vertical sides, to the depth of the spade at the end of one half of the plot. The soil should be placed at the same end of the plot, but opposite the other half, where it will be ready to fill in the last trench. Then break up the bottom of the trench to the full depth of a fork. Take care to break up the soil in the middle and the sides of the trench. Next, a second strip of exactly the same width should be marked off, and for this purpose it is a good plan to keep a stick cut to the right length at each side of the ground which is being trenched. Put the line across at the end of your sticks to mark how broad the next trench is to be. Then take out the second trench, placing the soil from it on to the broken-up bottom of the first trench. A trench 2 feet (60 cm.) wide can be conveniently worked in three spits. Each time the first of the three spits to be moved should be the one farthest from the trench which is being filled in, and it should be placed so that it forms a good wall to the second trench. Then the second and third spits may be removed. The second trench, like the first, should be to the full depth of a spade before the bottom is broken up. To do this, it will be necessary to remove the ‘crumbs’ from the second trench with a shovel. When this has been done, the bottom of the second trench is broken up with a fork, and filled with the soil from the third and so on.

When manure is to be applied in double-digging, it should be spread over the broken-up bottom of the trench, and forked into the loose soil there. The manure may be spread over the ground in the same way as for single-digging, but each time before a top strip of soil is moved into the trench the manure is transferred to the broken-up bottom of the trench.