Cold Frames
In cold districts these frames can be of great assistance to the gardener in protecting young plants. Cold-frames can be easily constructed either as fixtures or as movable equipment, and they have many uses apart from growing seedlings for transplanting.

A frame made of bricks and covered over with glass should be about 9 feet long and 6 feet wide with a back about 12 inches high and the top sides sloping to about 9 inches.

A wooden frame could be smaller, movable, and constructed so that it can be taken to pieces. Portable frames have many advantages; being movable they can be taken to fresh soil. The more permanent ones require filling with fresh soil at frequent intervals.

To get best results from cold-frames it is necessary to manage them skilfully. Their main function is to control the temperature round the young plants and reduce the ill-effects of frosts. They should always be sited so that the glass face is towards the sun.

As well as reducing frost damage, cold-frames prevent excessive dampness in the soil. Though seedlings require some water, too much under cold conditions retards growth and can induce disease. Frost damage can be partly prevented by banking the soil round the walls of the frame during the winter. When frosts strike down on the glass front, cover the glass with sacks or straw. These must be removed each morning after the frosts have lifted.

Excessive dampness inside the frame is sometimes a problem. Remove the glass (or lights)
each morning and this dampness will be reduced when the warm sun heats and dries the soil. The best time to water plants in frames is between 9 a.m. and 10 a.m., when the air temperature is rising. Too much water must be avoided and it is necessary to examine the soil regularly before any water is added. A light sprinkling could be all that is needed.

The main reason for growing plants in frames is to promote early spring growth. It is essential that the seedlings receive no set-backs from the time they germinate until they are well established.

Plants grown in frames need to be "hardened off" before they are planted out into the garden. "Hardening off" is the process of acclimatization, and it must be done in easy stages. The greater the difference between the temperature and humidity inside the frame and outside, the longer this process will take.

If the seedlings growing in the frame are transplanted without having been properly hardened off they will be severely checked.

If the seedlings are in a box move the box to a sunny position each day for a week or so. If the seedlings are in the soil the light should be lifted a few inches for about an hour each day for the first week, and then extend this opening time gradually over the next fortnight or so. At the end of this period the lights can be removed.

Watch carefully for soil dryness when the seedlings are exposed; a light application of water will be necessary from time to time. A cold-frame is a worth-while piece of equipment in any garden situated in cold districts or in regions which have a late spring season.

Seed Boxes
Any shallow wooden box can be used for growing seedlings, but boxes 18 inches by 12 inches are the most convenient to handle and need not be more than 4 inches deep. If they are well made it might be necessary to drill holes in the bottom for drainage.

To prepare these boxes, place a layer of clinker or crushed coke on the bottom of the box and then add soil. This soil should have been enriched before with manure or compost.

A suitable mixture for boxes is 1 part loam, 2 parts sand, 1 part peat-moss or old compost, and 1 part well-rotted stable manure.

Before planting any seed make sure that the soil is damp and free from small stones. These stones will not be present if the soil has been passed through a screen. Lightly stir the soil and then sow the seeds.

From now on each box can be treated as if it were a seed-bed but, because boxes dry out more quickly than seed-beds, more attention must be paid to their watering.
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