Lack of light and cool temperatures over the last few weeks after the blast of heat and sunshine has slammed on the brakes on growth in the greenhouse. Sweet peppers and aubergines are slow get going and side shoot and the tomatoes look really lacklustre but the cucumbers in one corner, which don’t mind the humidity, are happier. I open the windows slightly rather than the door to circulate but avoid chilling draughts. One of the positives is that as soon as light and temperature levels increase these crops will soon get going, there’s bags of potential!
Keep twining cucumber stems round their supports and cut back the side shoots two leaves beyond the flowers and fruits, to increase airflow and reduce chances of mildew – keeping foliage dry, the plants well-watered and mulching also helps use resistant varieties like ‘Carmen’, my choice this year are well worth growing. Harvest cucumbers regularly when fruits are about 30cm long and water with high potash fertilizer to encourage further fruiting. Maintain humidity by damping down the floor of the greenhouse, I also mist cucumbers with a hand sprayer maintain humidity around the underside of the leaves this reduces problems with red spider (or two spotted) mite.
Check regularly for signs of pests, like whitefly and red spider mite. Before introducing biological controls use environmentally friendly sprays containing fatty acids, plant invigorators, plant extracts or plant oils – chemical residues will kill them. SB plant invigorator based on organic soap, controls a range of pest species including Whitefly, Spider Mite and Mealybug plus mildew and other fungal problems, it’s a useful foliar feed, too and is biodegradable, non-toxic and there is no interval between spraying and harvest, so it’s massive in a gardeners armoury. Whitefly can then be controlled Encarsia formosa, Red spider mite (or two spotted mite) by increasing humidity around the plant or introducing predators like the mite Phytoseiulus persimilis, midge Feltiella acrarsuga or a rove beetle, Atheta coriaria to keep them under control.
Feed fruiting crops like sweet peppers and chilli’s according to the manufacturer’s instructions, continue side shooting tomatoes, tap the open flowers to encourage pollination at mid-day on a warm, dry day and tie the stems to canes or supporting string as they grow allowing space for the stems to expand. Keep the compost moist as erratic watering causes splitting and ‘blossom end rot’.
Maintain a regular regime of feeding and watering with tepid water. It’s also helpful to learn how to judge this by the weight of the pots of other plants when the compost is wet and dry compost. When watering, give plants a thorough soak; a light sprinkle only encourages roots to the surface where they are more susceptible to drought. Potted pelargoniums should be fed with half strength tomato feed every watering and the compost should dry out completely before rewatering again.
I’ll be making a last sowing of French beans under glass early in the month and pinching out my melon plant beyond the fifth leaf and retaining the four strongest stems and hoping for a better crop than the single one I managed last year!