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.
Those that have been bearing through the winter require a night temperature of 65° to 70°, according as the weather is cold or mild. If in low pits in houses, cover the glass at night in preference to hard filing; give more or less air daily, according to the state of the weather; and keep the soil moderately moist, increasing the supply of water and the moisture of the air as the days lengthen. Do not allow the leaves and young growths to become crowded, nor the plants to bear too much fruit at one time. Sow seed for succession crops in a temperature of 70°. Keep them near the glass as soon as the young plant appears. A good way is to sow two or three seeds in a 4 or 5 inch pot, half-filling the pots with light loamy soil, and as soon as the plants grow above the rims of the pots, to earth up the planrs: in this way no check is sustained. If to be grown on trellises, they should not be stopped.
Those that were sown last will be ready to plant out by the middle of this month. Cucumbers like a rather light rich loam, with a third part of well-rotted mushroom-dung or leaf-mould, sifted finely and well mixed with the soil. If to be grown on trellises near the glass, plant a plant every 2-feet run of the house. Plant deep, up to the seed-leaf, and train the leader without being stopped; but stop the lateral growths at each joint, where a fruit, and in some cases two, will appear and swell. Water always with water at 80° to 85°, and keep the night temperature at 70°, giving more or less air daily to prevent spindly growths.
Do not exceed 70° at night for the present. Cucumbers require more moisture at the root and in the air than Melons, and soon suffer if they are allowed to become dry at the root. If sudden bright sunshine succeeds a few days of dull weather, they will flag, and should not be allowed to do so; and some thin material, such as tiffany, is best for shading with under such circumstances. Stop the lateral growths, and they will show fruit at every joint; but do not allow them to bear too freely when young, or it will cripple them, and they will not bear so well afterwards. Sow and plant for succession crops as directed for Melons.
Increase the temperature to 75° on mild nights when sun-heat can be taken advantage of in the afternoon. The early-planted plants will now be bearing freely. Do not allow them to bear too many at a time, or some of the freer sorts, such as Volunteer and Sion House, will exhaust themselves. The disposition to ramble and grow will decrease as they come in a full-bearing state. Mulch them with rotten manure, and maintain a moist atmosphere; and, above all, see that they do not suffer for lack of water, if in shallow borders with hot-water pipes under them. Plant out later-raised plants as soon as they are established in 5-inch pots, and train as described in former "Calendars." Sow for succession in later crops.
Plant out for late summer and autumn supplies. Those now in full bearing will require copious supplies of water, and if from long - continued bearing they should show signs of flagging energy, top-dress the bed with well-decayed manure; old mushroom-bed manure they do well with. Keep thrip, green-fly, and red-spider at bay by the usual preventives and remedies. Those that have been in bearing all winter may, if others are sufficiently advanced to keep up the supply, be torn out and their place occupied with Melons, or, if required, planted again for Cucumbers.
Now is a good time to plant out a quantity of plants for late summer and autumn supply. In England they do well enough in frames after bedding-plants are turned out, but in Scotland it is necessary to have them where there is a command of artificial heat, or mildew will ruin them. For further directions see former Calenders.
Water those in full bearing copiously with manure-water. Remove all old and tarnished foliage and unproductive wood as fast as they can be replaced with that which is young and healthy. Syringe regularly on fine afternoons, and shut up with strong sun-heat, so as to do with as little fire-heat as possible. In the south they do well at this season in cold frames, but in Scotland they are precarious and shortlived without more or less fire-heat.
Those that have been in bearing all summer may now be partially cut in, all fruit removed, be top-dressed with rotten manure, and kept at 75° heat at night, and they will soon make young wood and begin bearing, and give a supply till late in autumn. See that those in full bearing do not want for water at the roots, and syringe them freely on fine afternoons. About the middle of the month is a good time to sow for winter-bearing plants, or they may be produced from cuttings at the end of the month. It is desirable to get them well established while the days are yet long, and less fire heat required.
Plants raised from seed sown about the middle of August will soon be ready to plant out. A light moderately-rich soil is best for winter Cucumbers. Grow them on with as much light and air as possible, in order to get them strong and healthy before shorter and duller days arrive. Plants still in bearing should be watered occasionally with liquid manure. Keep the temperature from 70° to 75° at night. If a low temperature is allowed at this season, mildew is sure to attack and destroy them. All symptoms of it should be checked by dusting the affected parts with flower of sulphur.