This section is from the book "The Gardener's Monthly And Horticulturist V24", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
"P. F.," Jersey City, N. J., in your November Gardener's Monthly, asks for a few hints on strawberry forcing, which no doubt will be interesting to most readers of this paper. I will state the method I have most successfully fruited them. The first thing is to get a mixture of soil three parts good rotted sod, previously cut from an old pasture and one part well rotted manure thoroughly mixed. Fill as many three inch pots as the required number of plants you wish to force, sink them to their rims alongside of the rows from which you propose to obtain your plants ; this should be done as early as possible, for in this earliness depends the success. Layer the young runners into the three inch pots; keep them well watered, and in about three weeks they will be rooted nicely. Be careful only to have one plant in a pot, as one plant produces better results than two or three. As soon as the small pots are filled with roots, they are ready to be potted into six inch pots which I consider the most suitable. They should be potted with the soil above described, rather firm. Then stand them in a open, airy situation; never allow them to get dry,but encourage them to make as much growth as possible, so as to get the six inch pots well filled with roots.
If not well filled with roots before the end of the season you might as well throw your strawberry plants away as to attempt to force them. If it is convenient, after the plants are potted they had better be plunged to the rim in sawdust, coal-ashes or waste tanbark, which will keep the plants moist. Be careful not to plunge them or place them anywhere for the worms to get through the bottom of the pots. Leave the plants in this open situation until the middle of November. Then they should be put in a cold frame, the pots plunged to their rims in some light material, or an old hotbed pit, filled with dry leaves would do as long as it keeps the roots from freezing, and so they can be got at easily at any time for the forcing department. The ashes should be put on to keep the plants from severe freezing, but air should be admitted on all favorable occasions to keep them as cool as possible, for one should imitate nature as near as possible; therefore, the plants should be in their dormant state at this time.
Now the time of introducing the first lot of plants to heat will be considered with due regard to the time when ripe fruit is expected.
If wanted by the first of March, the first lot had better be brought in about December 15th or 20th, into a heat not exceeding 45° or 50°; about this temperature should be maintained until the fruit is set. After the berries are set the temperature may be increased to 60° by night and 80° by day, with sun heat, with plenty of moisture. The plants should be liberally watered with liquid manure while they are swelling their fruit. As soon as the fruit begins to color, less water should be applied and more air; it makes the fruit firmer and better flavored. Of course a batch can be brought in every two weeks in succession. We are not yet done with those forced plants, for if planted out in the garden in April, and all the runners kept pinched off, they will fruit again in autumn, when a dish of strawberries would be very acceptable. I have forced many hundred strawberries every year, for eight years, until this year. But here, I am sorry to say, we have not the room or conveniences.