Under Cool Glass
Tomatoes, peppers, cucumbers, aubergines will all be ripening this month. Keep them picked at the peak of freshness. A delay in picking can cause their skins to become tough.
Tomatoes need warmth, not just sunshine, to ripen, so close greenhouse vents and door in the late afternoon, to conserve heat, now that the evenings are becoming cooler.
It is better to water in the morning so the atmosphere doesn't become too humid overnight, which in turn can lead to fungal problems. However, it is necessary to maintain a regular watering regime to avoid 'blossom end rot'.
If you haven't already 'stopped' your tomatoes, now is the time to do it, by pinching out the growing tip at the top of the main stalk. This will also serve to divert resources into ripening the existing crop rather than produce unproductive new growth. Any new trusses of blossom that would have been produced will not have had time to develop without the application of additional heat. Continue with the de-leafing of the vine, so that only the top 12”-15” of leaves are left.
Treat cucumber vines similarly.
Like July, there are lots of crops to harvest this month.
If you escaped infection of your potato crop by late blight, either by preventative spraying, or pure luck, now is the time to lift the last of your early and second-early potatoes. They will not increase in yield by much more now, and the longer they are left in the ground the more vulnerable they are to attack by pests, especially slugs, if the weather turns wet. Late maincrop potatoes should be left until next month or October, providing they are continuing to grow healthily.
The alliums, shallots, spring planted onions and garlic will become ready for harvesting when the leaves start to turn yellow and flop over. Don't force the issue by bending green leaves over, as this will promote attack by disease. Lift them gently with a fork and allow them to rest on the soil for a few days, to allow the leaves to become papery, then remove them for further drying, cleaning and storing under cover in airy conditions. Any onions that have thick necks should be used first as they will not store well.
Continue to pick runner and French beans, courgettes and cucumbers at regular intervals to ensure they don't get too stringy or tough. If you have too much to cope with, now is the time to impress your non-gardening friends with your expertise, by sharing. Or, failing that, you could just freeze your runner and French beans ready for the winter roasts (and then impress your dinner guests).
Earlier sowings and plantings of sweetcorn will start to ripen this month. This will be indicated by the tassels on the cob shrivelling and turning brown. Test the cob for ripeness by sticking a fingernail into a kernel and seeing if the liquid that oozes out is milky, which means that it is ready to pick. Don't delay in picking or eating as the cob will quickly lose its sweetness and become starchy. Freeze any surplus as quickly as possible after picking.
Make sure that all vegetables receive adequate watering, especially during any dry spells, as lack of water at this critical period can lead to bolting of salad crops, splitting of carrots and other root vegetables and loss of flowers in peas and beans.
If you are growing marrows, (or your courgettes have escaped!), lift them off the ground and rest them on some loose straw. This will allow them to ripen evenly all round, and prevent them becoming soiled or rotting. Some of the larger leaves can be removed to increase air-flow and exposure to sunlight to aid their ripening.
Sow Spring Cabbage. Keep an eye on late summer cauliflowers, and harvest as soon as they form decent-sized curds, any delay and the curds will 'blow'. Share or freeze any surplus.
Ensure that weeds are not allowed to set seed, by regular hand weeding or hoeing. Weeds will compete with your existing crops for water, light and nutrients and if allowed to set seed will present further problems next season. They will also act as havens for pests and diseases.
As crops are cleared, remove any detritus, weeds and diseased leaves, and fork over the ground. If the land is not needed for planting or sowing a follow-on crop, sow a green manure crop of Italian ryegrass, winter tares (vetches), or red clover. These will smother any new weed growth, their roots will improve the the soil structure and they will help hold onto soil nutrients. They can be dug in during the early spring and will improve the land for next year's crops.
Alternatively, you can cover the bare ground with black polythene sheeting. This will warm the earth encouraging the germination of any weed seeds, which will then die from lack of light. Occasionally, lift the plastic for a few days during mild weather. This will allow the birds to feed on slug and snail eggs and other insect pests and allow sufficient light to reach further weed seeds and initiate more germination. When the plastic is replaced the germinating weeds will be killed off. This is a method of soil improvement called 'solarisation'. Do not leave the plastic in place without lifting occasionally, as this will render the soil stale and stagnant and encourage disease. It will aso provide a haven for slugs and snails and rats and mice.
The Fruit Garden
If you have not already done it, ensure that all the old leaves are removed from your strawberry plants as soon as the crop is harvested. Also remove any straw and any weeds from the bed. If the bed is in its first year, any runners can be raked back into the rows and allowed to re-root to increase the number of plants in the row, to form a 'matted row'. If the bed is older, then remove the runner plants entirely, either disposing of them or creating a new row, on fresh ground, to replace an older row that is past its best. Strawberry plants go into decline after about their fourth year, so don't hesitate to dig them up and dispose of them, as keeping them beyond this time will only lead to reduced crop yields and an increased likelihood of disease.
Perpetual or ever-bearing strawberries will start to ripen this month for a late crop. They will carry on flowering and fruiting until the first frosts, but the later fruit may not get sufficient warmth to ripen. Leave strawberry varieties of this type until January or February before de-leafing and runner removal, though straw and weeds should be removed earlier when the crop is finished.
Summer-fruiting raspberries will finish this month, so cut out the fruited canes down to ground level. Also any weak new canes can be removed, leaving only 4-6 sturdy new canes per stool. These should be tied onto the supporting straining wires so that they are not damaged by high winds during the winter months. Loganberries, tayberries and blackberries should be treated in the same way when they have finished fruiting.
Autumn fruiting raspberries (primocanes) will start to come on stream this month and will carry on fruiting until the frosts. So, still keep the cream handy. The canes (all of them) are not cut down until February, though an earlier crop can be obtained next season if any un-fruited sturdy new canes are left un-pruned. This will give a two-phased fruiting period next year, the un-pruned canes fruiting earlier, and the new canes arising next spring, giving a later crop.
Summer pruning of currant and gooseberry bushes should be carried out, if not already done so, and any stragglers of late-ripening fruit picked.
Some varieties of plums and other stone fruits will be ripening this month.
Apples and pears can be summer pruned towards the end of the month. This will help keep the trees or bushes to a manageable size and prevent overcrowding of branches. It will also let the autumn sun to reach the maturing apples and pears. It is sunlight that gives apples their 'rosy cheeks', so those apples at the centre of the bush, hidden from the sun will stay greener. They will still ripen and taste the same eventually, but not appear as appetising, perhaps. The new growth that has arisen this year should be cut back to above a bud, leaving about a hand's width of growth remaining. This will encourage the formation of flowering buds and fruit spurs for next season. Some varieties of early ripening apples and pears will start to be ready for picking this month. They are usually eaten as picked from the tree, as they don't usually keep well in store.
Pests & Diseases
If thinning late carrots, remember that the carrot fly is still active, so gather up all the thinnings so the smell does not attract them. Keep the crop covered with fleece, or take other preventative measures to avoid attack.
Keep a watch for aphids and other pests, such as cabbage white caterpillars. Deal with them promptly. Slugs and snails, too.
If potatoes have been infected with blight, do not delay, but cut off the haulms (stems) immediately it is detected. Burn or dispose of the affected haulms but don't compost them. Leave the tubers in the ground for a few days only, to allow any fungal spores on the soil surface to die, then lift the tubers, dry off and store. Examine them frequently to ensure that no blight has got into the tubers.
If no blight has been detected, either on potatoes, or other solanaceous crops such as tomatoes, peppers or aubergines, do not relax your guard, but continue with preventative spraying with either Dithane or Bordeaux Mixture. Take a note of, and heed, the 'harvest interval' given in the manufacturer's instructions. Watch this web site's message board for blight alerts.
As you lift your potatoes, keep a watch for signs of disease; powdery scab, scab, potato cyst eelworm are things to look out for. Potato cyst eelworm forms tiny nodules on the potato plant's roots. Don't confuse them with tiny immature potatoes which grow on the underground adventitious shoots. Only store sound healthy tubers to minimise the risk of infection spreading. If you've got blight among the tubers, the unmistakable smell will soon let you know!
Sweetcorn can become infected with a fungal disease called 'smut' at this time of year; the cobs will be swollen with a grey to brown colour to the kernels. If you don't remove and dispose of the cobs promptly, they will swell further and burst open to release thousands of powdery fungal spores which will infect healthy plants.
Pea moths are active; look out for their tiny caterpillars. Fungal diseases, such as powdery mildew or chocolate spot (on broad beans) may arise on your peas and beans. Powdery mildew may also affect courgettes, gourds, pumpkins and cucumbers too.
On ripening tomatoes a variety of diseases or conditions may arise. Blossom End Rot, caused by irregular watering and lack of calcium, Ghost Spot, spread by careless watering or splashing of the fruit trusses, or virus infections can all appear and spread rapidly. They can also be affected by late potato blight. Two-spotted spider mite may also appear if conditions are very dry and warm. Some tomato varieties are more genetically pre-disposed to 'greenback' or blotchy ripening than others, particularly some of the older or heritage varieties, but the condition may be worsened by poor growing conditions and lack of nutrients. Ensure that de-leafing is continued to let the fruit get the warmth of the sun to aid ripening. Rogue out any badly affected plants.
As you lift, and dry-off the onion crop, examine them for disease before storage. The necks can be soft and squishy with a grey or black mould of 'neck rot', or they may have been affected by 'white rot' or by onion eelworm which attacks the base of the bulb. The eelworm can cause swelling and distortion of the onion plants and bulbs. In either case the stored bulbs will rot and infect healthy bulbs. Next season grow your onions on fresh ground that has not grown onions before or for an interval of several years, and as with all your crops, maintain a good crop rotation regime.