Now’s the time to sow Fennel, oriental vegetables like mizuna greens and Pak Choi, rocket, coriander dill, spinach, claytonia and land cress in modules. Germination will be fast and they can be planted out by mid-August for cropping in autumn.
Later in the month August sow spinach, spring onions, lettuce and spring cabbage for transplanting outdoors. In hot conditions make sure you move them outdoors soon after germination, protecting them with horticultural fleece from scorching sunshine and pigeons, which are particularly partial to brassicas, including oriental vegetables.
Continue sowing ‘cut and come again’ crops like mixed herbs, in pots, greenhouse borders or growing bags. Mixed salads can be started in shade under greenhouse benching then moved outdoors.
In late August sow spinach, spring onions, lettuce and spring cabbage for transplanting outdoors. If hot conditions persist then make sure you move them outdoors soon after germination, protecting them with horticultural fleece from scorching sunshine and cool winds on overcast days.
Take cuttings from non-flowering shoots of salvias and penstemons and pelargoniums and other tender plants. (It’s worth noting that soft fleshy cuttings like heliotrope or impatiens will root in water). Cuttings should be 10-15cm long, making a cut just below a leaf joint. Trim off the lowest leaves and pinch out the growing tip, then dip the cut end in hormone rooting powder knock off the excess then plant 3-4 around the edge of a 9cm pot of multipurpose compost mixed with a little grit or perlite to improve drainage. Keep the cuttings shaded in a greenhouse propagator. Once rooted move them into 3” pots and keep them in the greenhouse for planting out the following year.
Remove tomato leaves shading trusses of fruit, to speed up ripening, plus some below the trusses around the base to improve air circulation and reduce the chances of tomato blight, but don’t remove too many. Removing the lower leaves enables you to see the base of the plans so you can apply water around roots. Avoid wetting the leaves and use a solution of Epsom Salts to remedy magnesium deficiency. Keep the compost constantly moist to reduce the chances of blossom end rot.
Use your greenhouse fan on ‘cool’ to circulate the air, or move containerised plants outdoors into shade.
Harvest crops like aubergines, cucumbers and tomatoes, chillis and sweet peppers so that the remaining fruits mature. Aubergines should be harvested while the skin is glossy, cucumbers once they have reached 12” long and chillies and sweet peppers when the whole fruit has coloured up.
The sweet pepper in the photograph has an unusual history. Last August, I found it as a small seedling growing through the plug hole of the sink in the utility room. After teasing it out carefully, with cocktail stick, trying to retain as many roots as possible, it was carefully planted in the same pot as a Begonia ferox in my office. It lived with its chaperone, who took care of it over winter under grow lights, surviving temperatures down to 15C before bursting into growth in spring. It was a challenge to remove the small plant with as much root as possible but it was planted out early when the Begonia was repotted and cropped in mid-July, instead of late summer. It was certainly the most expensive sweet pepper I have ever eaten but much of the pleasure and excitement came from the success of my little project. Happy Gardening. Matt