General Hints and Advice On Growing Cucumbers
GROWING CUCUMBERS IN A HEATED GREENHOUSE
Sowings may be made between February and May where sufficient heat is available. Cucumber seed should be sown singly either in 7.5cm (3in) pots or spaced 2.5cm (1in) apart in boxes or pans. A temperature of 15°C (60°F) is necessary for the ordinary varieties and 21°C (70°F) for the “All Female” types. When sowing in 7.5cm pots, some people prefer to no more than half fill the pot at sowing time, subsequently adding more compost at a later stage and avoiding the disturbance of re-potting and yet encouraging necessary vegetative growth.
If sown in boxes or pans, the seedlings should be pricked off into 7.5cm (3″) pots after seven or eight days and must be planted fairly deeply with the seed leaves almost touching the soil surface, or the plants will become leggy. Do not completely fill the pot with compost, to allow topping-up with suitable compost as the stem elongates.
About three weeks after sowing, the plants can be planted out 2 per growing bag or individually into a 25cm (10in) pots. After planting out, a day temperature of between 15°C (60°F) and 21°C (70°F) should be maintained and the night temperature should not be allowed to fall below 15°C (60°F).
Cucumber plants should be trained up towards the roof with laterals tied to horizontal wires or strings. The tips of the laterals are usually pinched out after two leaves from the main stem, provided both axils of the leaves are showing fruit buds. All male flowers should be removed and also any fruits which are being produced on the main stem itself. It is most important to ensure that the plant receives no ‘check’ (e.g. temperature drop, incorrect watering, lack of nutrients, etc.) as its development may be affected.
Over-cropping must be avoided and it is sometimes necessary to thin out the fruits in the early stages. Periodical top-dressing with a compost around the base of the plant is necessary, especially if young roots are showing. A constant supply of water at the roots is essential and the atmosphere should be kept reasonably moist by overhead spraying. Stagnant conditions must not be allowed to develop. When the first fruits start to swell feed at fortnightly intervals with a tomato fertilizer.
GROWING CUCUMBERS IN AN UNHEATED GREENHOUSES
Most of the greenhouse varieties may be grown under glass without heat, other than that produced by the sun, but sowing should be delayed until April or May, and it may even be preferable to use plants raised in heat and plant them out in April or May in the cold house. The general culture in the cold house would follow the pattern given for a heated greenhouse.
GROWING CUCUMBERS OUTDOORS
For outside growing in the open, one of the special outdoor varieties should be selected and there are now a number of heavy yielding sorts capable of producing exceptionally high quality fruit which in appearance closely resembles that of greenhouse varieties.
The Cucumber seed may be sown direct in a prepared bed in May, or in pots in the greenhouse, or frame in mid-April for planting out in May when the danger of frost is passed.
Sow or plant in rows 90cm (3′) apart each way to allow for the natural trailing habit of the plant. It may be necessary to protect the young plants with a cloche or fleece during cold weather.
The tips of the shoots should be pinched out when five or six leaves have developed and no further stopping should then be necessary.
ALL FEMALE HYBRID CUCUMBERS
Cucumber seed should be sown in boxes in a temperature of 21°C (70°F) and the seedlings should have developed two true leaves and be ready for potting into 75mm (3″) pots in about 7 or 8 days. Plant deeply with the seed leaves almost touching the soil.
The plants should be put into their final quarters at an earlier stage than with normal varieties, as these Cucumbers are inclined to produce fruit very early and, therefore, tend to neglect vegetative development if left in the pots for too long a period.
It is most important to have plants with a strong root system and to stimulate the vegetative growth at this period all side shoots must be removed in the first 6/8 leaf axils of the main stem to prevent premature fruit setting and to encourage growth; it is important that this should be done as early as possible.
Lateral shoots should be trimmed in good time and this must be confined in the early stages to pinching off just the top of the shoots two leaves beyond the flower, whereas with normal flowering varieties the laterals are removed when the flower buds start to yellow.
The quality of the fruit obtained from the laterals is much higher and only in the case of very vigorous growth should a few fruits be left on the main stem in the top of the plant.
If the growth becomes too strong the night temperatures can be reduced and this should help to stimulate fruit setting. Provided no other type of Cucumber is grown in the vicinity there is no problem of cross fertilisation and the production of bulbous fruits sometimes seen in normal varieties.
ALL FEMALE VARIETIES PRODUCING MALE BLOOMS
Grown under ideal conditions these plants will only produce female flowers. It is, however, known that a number of separate factors associated with the precise growing regime may cause the plants to perform out of character and result in the production of a number of male flowers early in the growing season.
Acute temperature variations (too high or too low), unbalanced feeding, incorrect irrigation, can all bring about conditions which will cause the plant to produce some MALE blooms.
Any male blooms should be removed as soon as they are identified and the cultural factor(s) must be corrected, paying very careful attention to temperature requirements and irrigation.