This section is from the book "Commercial Gardening Vol3", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
Very rarely indeed are Apples grown alone. They are usually under-cropped with Gooseberries, Currants, or Raspberries, and sometimes entirely with vegetable crops like Rhubarb. The above diagram (fig. 330), taken from an actual market garden, shows how some growers crop their ground.
The Apple trees in this case, represented in the diagram by the letter A, are grown as bushes at 10 ft. apart every way, making about 435 to the acre. Between them one Gooseberry bush (White Lion), represented by the letter G, is planted, giving also 435 plants to the acre. In between the rows catch crops of such vegetables as Cabbage, Lettuce, Spinach, Leeks, Potatoes, etc, are taken in the rows running north and south.
Apples grown in this way, when properly pruned and cared for, bear from 20 to 60 lb. of fruit in their sixth and seventh years. It might therefore be assumed that when ten years of age there would be an average of 1 bus. of fruit (40 lb.) on each tree every year, making a total of 435 bus. (or 17,400 lb.) of good fruit. At 3s. per bushel this represents a gross revenue of £65, 5s. per acre for the Apples alone.
To this must be added the Gooseberries. It may be assumed that half a sieve or 1/2 bus. would be a fair crop for a well-established bush. Reckoning 30 lb. to the half-sieve, the yield of gooseberries would be 12,050 lb., something over 5 tons to the acre. At an average price of 1s. 6d. per half-sieve, the gooseberry crop would realize £32, 12s. 6d. The Apples and Gooseberries therefore together yield a gross return of £97, 17s. 6d. The vegetable catch crops, in the first few years at any rate, would realize sufficient to pay the expenses of labour, and this latter item might be put down roughly at £20 per acre per annum.
If Red Currants were grown instead of Gooseberries, the average crop from established plants might be reckoned at 3 tons to the acre, and as these are usually worth £10 to £12 or more per ton, the receipts would be somewhat higher.
Black Currants would be a still more valuable crop, assuming that they were fairly free from attacks of "big bud" (see p. 157); 435 bushes to the acre should yield, say, 3 tons of fruit, which, at £20 a ton, would be about twice as lucrative as the Red Currants.
Fig. 331. - Standard Apples 18 ft. apart, with under crop of Rhubarb - 134 Apple Trees and 5000 Rhubarb Plants to one acre.