Help the harvest cross the finish line
From ripening squashes to early apples, this week is about helping established crops finish well while making a few careful sowings for the colder months.
Photo: Amie Roussel via Unsplash
By the third week of August, many plants have stopped putting on masses of new growth and are concentrating on ripening what they already carry.
Pumpkins are swelling, sweetcorn is getting closer to harvest and the first apples may be ready to pick. This is also a useful week for sowing hardy leaves that prefer the cooler conditions of late summer and early autumn.
The aim isn’t to begin another huge round of planting. A few small, well-chosen sowings are far more useful than filling every empty bed.
What to sow indoors or under cover
Overwintering onions
Sow overwintering onion seed in modules in an unheated greenhouse or sheltered cold frame. Starting them under cover can be more reliable than direct sowing in wet northern soil.
Winter spinach
Sow a hardy variety in modules for planting into a greenhouse, cold frame or sheltered container during early autumn.
Coriander
Sow in a pot on a bright windowsill or under cover. Cooler conditions mean it is less likely to run quickly to seed.
Winter lettuce
Make a small module sowing of a genuinely hardy winter variety. These plants can later provide leaves from a protected space.
Keep late-summer seedlings moist but not waterlogged. Good airflow is important, especially when warm days are followed by cooler nights.
What to sow or plant outside
- Winter spinach: sow a short row in a sheltered bed for autumn picking and possible overwintering.
- Mizuna: this quick-growing leafy crop tolerates cooler weather and can also be grown in a container.
- Mustard leaves: sow thinly and harvest while young for a milder flavour.
- Spring onions: sow a hardy variety for a small autumn crop or to overwinter.
- Turnips: make a final small sowing of a fast-growing variety for tender autumn roots.
- Green manure: sow phacelia or another suitable green manure on beds that won’t be needed for several weeks.
Newly sown beds may need protection from pigeons, slugs and heavy rain. Containers can be moved to a more sheltered position if conditions become particularly wet.
🎃 Help pumpkins and squashes ripen
Pumpkins and winter squashes need time and warmth to develop a hard skin suitable for storage. By late August, very small new fruits may not have enough time to mature.
- Remove tiny new fruits and fresh flowers if the plant already has several good-sized squashes.
- Pinch out the growing tip a couple of leaves beyond the final fruit.
- Place each developing squash on a tile, board or upturned plant pot to lift it away from damp soil.
- Turn fruits only if they move easily. Forcing them can damage the stem connecting them to the plant.
- Remove only leaves that are badly damaged or completely blocking light from the fruit.
Keep watering during dry conditions while the fruits are swelling. Avoid soaking the developing fruits or allowing them to sit in water.
What may be ready to harvest
- Sweetcorn: check when the silks have turned brown. A pressed kernel should release a milky liquid when ripe.
- Early apples: lift and gently twist the fruit. A ripe apple should come away without pulling hard.
- Plums: pick ripe fruit regularly, particularly before rain causes the skins to split.
- Blackberries: choose fully black, plump berries that come away easily.
- Beetroot: lift medium-sized roots before they become oversized and woody.
- Second-early potatoes: lift as needed. Allow any potatoes intended for short-term storage to dry before putting them somewhere dark.
- Tomatoes: harvest fruit as it colours. Split or damaged tomatoes should be used immediately.
- Herbs: pick mint, parsley, oregano and thyme for drying or freezing.
Prune blackberries after fruiting
Cultivated blackberries generally produce fruit on canes that grew during the previous year. Once an old cane has finished fruiting, it can be removed.
- Identify the older canes that carried this year’s fruit.
- Cut those canes down close to ground level.
- Leave the strong new green canes for next year.
- Tie the new canes loosely to wires or another support.
- Remove any weak, damaged or badly positioned growth.
If fruit is still ripening, wait until the cane has completely finished before pruning it.
Jobs around the garden or allotment
- Check brassica netting for gaps and make sure growing plants aren’t pushing tightly against it.
- Look beneath cabbage and kale leaves for caterpillars or clusters of yellow butterfly eggs.
- Support heavily laden apple, pear and plum branches before they split under the weight.
- Remove fallen fruit from beneath trees to reduce waste and avoid attracting wasps.
- Cut back herbs after harvesting, but avoid cutting deeply into old woody growth.
- Clear plants that have completely finished cropping and add healthy material to the compost heap.
- Label autumn sowings. Similar-looking rows of young leaves are surprisingly easy to forget.
- Check water butts and gutters for blockages before heavier autumn rain arrives.
Preserve some summer herbs
Freeze soft herbs
Chop mint, parsley or coriander and freeze them in an ice-cube tray with a little water. Once frozen, transfer the cubes to a labelled container.
Dry woody herbs
Thyme, rosemary, oregano and sage can be tied in small bundles and hung somewhere warm, dry and well ventilated.
Store herbs only when they are completely dry. Any remaining moisture can cause mould to develop inside the jar.
Start a harvest weighing chart
Ask children to help weigh a courgette, handful of beans, bowl of tomatoes or another harvested crop.
Record the weight on a simple chart and add to the total each time something is picked. Younger children can draw the food, while older children can help add the numbers.
By the end of the season, you will have a record of how much food came from the garden—even if it was all grown in containers.
This week’s quick checklist
- Sow a small pot of winter spinach
- Start overwintering onions in modules
- Pinch out finished squash growing tips
- Raise pumpkins away from damp soil
- Check sweetcorn for ripeness
- Pick early apples with a gentle twist
- Prune blackberry canes after fruiting
- Check brassicas for caterpillars
- Dry or freeze surplus herbs
- Begin a harvest chart with children