Growing Greenhouse melons
Despite the fact that cantaloupe melons can be grown in frames or under cloches, you will get better and earlier fruit in a greenhouse. Furthermore, this is the only place where you can grow sweet varieties and watermelons. Thepreparation for greenhouse plants can be the same as for frame-grown plants. You can also grow them on a hotbed; they enjoy pampering and if you want really good early melons, this is the way to grow them. If you have a greenhouse or frame which has undersoil electric heating wires this is ideal. If not, with a little effort, you can make an old-fashioned hotbed.
Put down a layer of fresh manure 45 cm (I2) wide and 15 cm (6”) deep. Turn this over occasionally for a few days so that excess nitrogen is given off as ammonia. Then cover with a layer 30 cm (1’) deep and 60 cm (2’) wide of good loamy soil, thus forming a mound.
A hotbed can also be made using straw instead of manure. Put down a layer of straw 60 cm (2’) thick, sprinkle it with sulphate of ammonia, and then saturate it with water. Cover the straw with loam in the same way as for a manure bed.
Seed is sown in the same way as for frame cultivation, but can be done in early spring, or even late winter, if you can maintain a suitable temperature, ie. 16°C (60°F) minimum.
When planting in the greenhouse, follow the instructions for planting in frames, but space the plants farther apart—about 45-60 cm (1-½ – 2’)—and put a 60 cm (2’) cane behind each.
Greenhouse plants are normally trained vertically on wires. Run “the wires horizontally from one end of the house to the other, attaching the ends securely to the framework, beginning 45 cm (18”) above ground. The wires should be spaced about 23 cm (9”) apart and about 30-35 cm (12-14”) away from the glass. The stems of the plants are then tied to the wire with fillis (soft string) or raffia as they grow. Once planted, or if necessary before this, pinch off the growing point at about three leaves and allow two sideshoots only to develop, one on each side of the plant. Train these upwards to the wires, with the support of the cane if necessary.
Most gardeners select four fruits (two on each main stem) but if you want early fruits of good quality select only two. Remove all unwanted fruits.
Let the main sideshoots grow up to the roof before pinching off the growing point, and let sub-sideshoots grow so there is a good but not cramped mass of foliage. Do this by either cutting off the sub-sideshoots after a few leaves, or by removing them completely, and repeat this thinning every few days once enough foliage has developed, but not so much that it becomes a shock to the plant.
Open the ventilators when the temperature in the house reaches 27°C (80°F) but close them again in the evening to preserve warmth for the night. As with melons in frames, give extra ventilation once the fruit begins to ripen.
Damp down the staging and floor to keep the atmosphere moist. It also helps to lightly spray or syringe the plants with water once a day, especially in hot weather, when red spider mite is most likely to be troublesome. Water regularly and heavily, until the fruit begins to ripen, then gradually decrease it.
Support the developing fruits by nets attached to the training wires above. Special melon nets can be bought but a net can be made quite easily out of a square of 5 cm (2”) netting. The square should be big enough to accommodate the expected size of your variety. Loop a piece of string through each corner of the net and tie to the supporting wire above.