August is such a great month for harvesting, and usually the most productive month in the vegetable garden. There’s still a little time to get a few extra vegetable plants in the ground as well, but we will soon stop shipping summer plants (probably in the 2nd week of August) so that we can move our polytunnels over to sowing seed for autumn and winter growing.
What to harvest
The below will depend a little on when your plants went in the ground, and the weather conditions that you’ve had in your area, so treat it as a loose guide that assumes you planted in May/June.
- Leaves of all types, from lettuces to spinach, chard and kale. Some, like Wild Rocket, Mizuna and Frills Mustard, are likely to flower now. If this is the case, let the flowers attract the bees but cut them back/pull the plants out before they go to seed (unless you want them to spread!)
- Tomatoes, chillies and peppers should start ripening this month, and you should be able to harvest aubergine too if you planted them early in the season. If you planted these more recently, they’ll take another few weeks.
- Pick beans and peas regularly. If you would like to store some dried beans (particularly borlotti) to use later in the year, leave the pods to dry out fully on the plant before harvesting.
- Summer squash, courgettes and cucumbers will also be ready this month, but leave winter squash and pumpkins a few months more. It is worth pruning winter squash/pumpkins a little to leave just 2-3 fruits on each plant if yours are a little behind this year. This’ll help the fruits to swell and ripen before late autumn.
- Sweetcorn should be ready soon! Wait for the tassels to turn dark brown/black before harvesting.
- Summer sprouting broccoli might be ready and you may even start to see the first of your cabbages and cauliflowers towards the end of the month.
- Potatoes, turnips, swede, beetroot and carrots are all harvestable in August. For main crop potatoes, wait until the plants have flowered and the leaves start turning yellow. For the root veggies, you should see the crown peeping above the soil surface which will give a good indication of its size before you harvest them (you can carefully scrape away the soil to check if they are hiding!)
- Onions and shallots can be harvested once the leaves start to turn yellow. Harvest on a sunny day and leave them to dry out before storing them.
- If you’re growing soft fruit, you should have lots of berries and currants to pick. Get them before the birds do!
Other crops will need a little longer – celeriac and parsnips will not be for a few more weeks, brussels sprouts nearer to Christmas, celery in September probably, or at the end of August, and leeks probably need a few more weeks too.
What to plant
You can fill the gaps with these last-minute summer plants for an autumn harvest:
- Lettuces & salad leaves
- Celeriac, turnips & swede
- Kale, broccoli, cabbages, cauliflower
- Leeks, beetroot and fennel
- Chard & spinach
- Beans & peas, but pinch out growing tips early on
Jobs to do
The main focus this month will inevitably be on watering, weeding and harvesting. But there are a few other things to do this month:
- Cut back/pull up wild rocket and mustard leaves after they flower and before they go to seed.
- Cut back flowering herbs like mint, marjoram, oregano and chives. They will come again.
- Add old plants/foliage to the compost pile. Once you have harvested the last of any crops, pull them up and add the foliage to the compost pile.
- Prepare empty spaces for autumn. Whether or not you plan to plant in autumn to keep growing, or will be putting your veg patch to bed for the winter, we’d recommend adding a good mulch of fresh compost or well rotted manure towards the end of the month. This will help to rejuvenate the soil, and will also help to suppress weeds. If you’re not growing in the autumn, then cover the mulched beds with black polythene too once your season comes to an end.
- Make preserves and pickles. For any gluts, it is well worth setting aside a day or two to make pickles and chutneys to preserve them. You can also freeze quite a lot.
- Feed plants with a liquid feed or wormcast fertiliser. This is particularly beneficial to fruiting plants like tomatoes and squashes.
- Keep slugs at bay. A quick dusk patrol, some traps and keeping the plot tidy will help. Watch out for slugs eating potatoes secretly – if this is a problem it is best to harvest potatoes and store them rather than leaving them in the ground.
- Keep brassicas protected from cabbage white butterflies and pigeons with an insect proof mesh.
- Earth up or stake taller plants like broccoli and sweetcorn, as August often brings windy days.
- Cut off or plant up strawberry runners
Pests & Diseases
- Caterpillars are likely to be around, particularly on brassicas, as butterflies lay eggs this month. Net your brassicas where possible, and check the undersides of leaves regularly for eggs/young caterpillars – you can just wipe them off.
- Blight could strike at any time – remove affected leaves as soon as you see them on potatoes or tomatoes to try to prevent it from spreading. If potato plants are badly affected, cut down the foliage altogether (you can then harvest the tubers as and when you are ready for them)
- Powdery Mildew is likely to affect cucumbers, squashes and pumpkins. Remove badly affected leaves to prevent it from spreading, and make sure you water consistently.
- Aphids could be a problem now so check leaves for this. They can get particularly bad in the greenhouse where there are less predators to eat them.
- Slugs and snails will be out in the rain and at dusk, so keep laying down beer traps, and using other preventative methods to keep your crops safe.