This section is from the book "The Gardener V1", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
Where early Figs are grown in pots, now is a good time to start them. They do best when plunged in a bed of warm leaves, giving a bottom-heat of about 80°. The temperature of the air should be the same as that recommended for Peaches. Keep them regularly moist at the root, and syringe them every fine afternoon, and otherwise keep the atmosphere moist. Should any of the plants require larger pots, shift them when put into heat; and those which have been for a few years in large pots will be the better for being turned out of them, and the crocks removed from among the roots at the bottom; the roots cut back sufficiently to allow of 3 inches fresh soil at the bottom of the pots, and top-dress the ball with horse-droppings. Brown Turkey and Raby Castle are excellent early-forcing varieties.
Continue to put last month's directions in force; increasing the heat a few degrees as the plants begin to break freely into growth, and increase the moisture in the air as light and heat increase. Look well to the regular supply of water at the root, and keep the bottom-heat steady at 80°.
Where the fruit are swelling, increase the night temperature to 60°, with 10° more by day. Figs like a moist atmosphere, and should be syringed every afternoon, and the air should never be otherwise than moist. Give careful attention to the matter of watering, especially if they are in pots; for if allowed to become over-dry, they will cast their crop; and stagnant water about their roots will produce the same effect. Give air regularly, more or less, according to the weather, to prevent the young growths from becoming weak and the foliage thin and tender. As soon as the growths grow to five or six joints, pinch the points out of them, or squeeze them firmly between the finger and thumb to stop growth, without causing them to bleed. Start later crops as recommended for February.
If the early crop be from trees in pots, great watchfulness is necessary in the case of watering. If they are ever allowed to become over-dry, the chances are that the fruit will fall off. Water two or three times a-week, alternately with guano or dung-water, and syringe freely at shutting-up time, and keep the air regularly moist. Stop the young growths at the fourth or fifth leaf. Where Fig-trees are planted in shallow inside borders, mulch with rotten dung, and keep the soil regularly in a medium state of moisture. Do not allow the trees to carry too many fruit at a time.
These will be swelling their crop rapidly, and require to be well supplied with manure-water, especially if they are old plants with their roots limited either to pots or borders of comparatively small dimensions inside the house. Syringe freely every fine afternoon, and frequently sprinkle the paths and surface of the border through the day; but gradually withhold moisture from the air as the fruit show signs of ripening, and increase the ventilation, otherwise the fruit will be insipid. When the second crop is forming in early houses, thin them out in time. A fair crop of large, well-swelled fruit is worth twice the quantity of small, skinny produce. Attend to stopping and tying down shoots in later houses, and avoid crowding in too much wood and foliage.
So soon as the first crop is gathered from early trees, give them a heavy watering with liquid manure and mulch with short dung, so as to support the second crop now showing. Avoid cropping too heavily, for two heavy crops in the season, to say nothing of some third, are hard work for them. Syringe freely on fine afternoons, and sprinkle the border and paths frequently in course of bright days, for the Figs delight in a moist atmosphere. Top-dress those in pots now swelling their second crop, and water freely with guano-water, and syringe the trees vigorously to keep down red-spider.
Where fruit are ripening cease syringing, and give a free circulation of warm dry air. Where the first crop is all gathered, and a second advancing, see that the trees are well fed. Give the border a mulching of rich manure, and water copiously. This of course applies to plants that are in large pots, or that have their roots cramped in a limited border, circumstances under which Figs bear most freely. The syringe must be used freely every fine afternoon to prevent red-spider, except, of course, where fruit are ripening. Figs are not fit for table till they have ripened into a soft pulpy condition, and are almoso ready to drop from their stalks.
Early trees from which the second crop is all gathered must not be neglected. If in pots, keep them well supplied with water, and free from insects by frequent syringing. Should they have more wood about them than is necessary for next season, remove it, and expose them to full light and air. "Where fruit are ripening the atmosphere must be comparatively dry, with a free circulation of air, or the fruit will be deficient in flavour. A well-ripened Fig is a delicious fruit, but if not well-swelled and perfectly ripened it is most insipid. Supply trees swelling off their crop with manure-water at the root - a moist atmosphere and frequent syringing is necessary to keep the foliage healthy, without which no fruit-bearing plant perfects its crop properly. It is just as reasonable to expect a human being to be strong and fat with pulmonary disease of the lungs, as to expect line fruit from trees with diseased or injured leaves.