This section is from the book "The Gardener V3", 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.
A number of these, according to the demand and space, should be put into heat every fortnight. Keep them near the glass, and begin with a temperature of 45° to 50° at night, increasing it to 55° by the time they show their trusses of bloom. Early-started crops now in bloom range from 55° to 60°, according to the weather. Give them a liberal supply of fresh air, but avoid currents of cold air passing over them. In all stages Strawberries require to be kept moist at the root, but are best not placed in saucers till the fruit are set, when they will do well with saucers under the pots, and a temperature of 65° at night, with 75° to 80° with sun by day.
These will now be nearly over, and any that are now to ripen may be removed to cold pits and frames, where they can stand on a cool bottom, otherwise red-spider will not be easily kept in check. As soon as runners can be had, lay the necessary stock for another year's forcing. They can either be laid in small pots or in soil laid between the rows of the parent plants. The finest runners are got either from early-forced plants or from runners pricked off in rows the previous autumn. At one time we pricked out a quantity every August for this purpose, and found these threw out the strongest and most healthy runners for laying the following June. For early forcing, make a point of having them shifted into their fruiting-pots the first week of July, and avoid large pots - 5-inch pots are large enough for the early crops.
See last month's Calendar. All should be in their fruiting-pots by the middle of this month at the latest; earlier if possible. Stand them where worms cannot molest them. Give them plenty of room. Remove all runners as they appear, and see that they never suffer from want of water. Syringe or water them overhead through a rose-pot every evening when the weather is hot and dry.
These, if shifted into their fruiting - pots last month, as we then recommended, will now be growing rapidly, and filling their pots with roots. Give them a liberal supply of water, and occasional watering with dung-water as they get well established in their pots. See that they are not standing too closely together - preventing a free circulation of air and light about them. They should be placed in an open airy situation. If any portion of the required stock still remain unshifted, not a day should be lost in getting them into their fruiting-pots. The great point is to attain well-ripened crowns, and pots as full of roots as they can hold. If they are disposed to root through the pots, lift them occasionally to prevent this. It is best for this reason to have them standing on board or trellis work, to prevent the roots leaving the pots.
If former directions have been carried out, these will now have well filled their pots with roots; and should the weather be hot and dry, give them frequent supplies of dung or guano-water. It is best to water them in the morning after this season, as the drier they are at night, the less likely are they to be affected with spot in their leaves. Keep them free from runners and weeds, and give them plenty of room.
If former directions have been attended to, these should now be ready to burst their pots with roots, and have large well-ripened crowns. During heavy rains, lay the pots on their sides, if they cannot be placed in cold pits or frames. When plants are late, place them in pits or frames, in a warm light place, and put glass over them to induce them to mature their growth better than if left in the open air.
These should now be plunged in cold frames, or removed to cold late Peach-houses, where they will be sheltered from rains. Or where no such protection can be made available for them, build them into stacks, laying the pots on their sides with the plants outwards, and fill up the space between them with ashes or sawdust. Put up in this way, they can readily be protected from severe frost by throwing mats or litter over them.
Put a quantity of these into heat, according to the number of plants and available room. The early Peach-house, or a shelf near the glass, is a good place to start them, as they do not do well with much heat thus early. If they can be set on a fermenting bed of leaves in a pit near the glass, it will be a great advantage to them. The mild bottom-heat will start them more kindly. Before putting them in heat, remove all decayed leaves, turn every plant out of its pot to see that the drainage is not deranged, and water them with clear lime - water to kill all worms, which, if not got rid of, will begin their injurious work immediately they are put into heat.
Put a number of these into heat every ten or fourteen days, according to the demand and space. Keep them near the glass, and begin with 45° at night, increasing the heat to 55° by the time the plants are in bloom. If a little bottom-heat can be afforded them, they start into growth more freely and more strongly. Range early crops now in bloom from 55° to 60°, and give air on all favourable occasions, avoiding currents of frosty air. When they are set, raise the heat a few degrees and water more freely. Strawberries are moisture - loving plants, but will not bear stagnant water; therefore avoid the too common practice of standing early-forced plants in saucers of water, and see that the drainage of each plant is correct before they are put into heat.
 
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