What to Do in the Vegetable Garden This September

AlanGardenMaster
Published on September 5th 2020
101
A large pumpkin fruit
September is harvest time for many crops, but time to sow and plant a lot of others!
Autumn is also a great time to improve your soil by making compost and sowing green manure crops.
Don't forget to look at my accompanying article on what to do in the garden in September, and my weekly tips.

Home grown fruit

  • Pick ripe apples and pears. If they come off the tree easily, without having to tug hard, then they are ready to harvest. If you cut one or two in half, look for brown pips to show that they are ready. Varieties harvested this month tend not to store well and should be eaten or cooked straight away. Those ready for picking next month should be varieties that will store better.
A close up of pear fruit hanging from a tree
Merton Cross pears need eating immediately
  • Remove and destroy any mummified tree fruits affected by brown rot. This reduces disease spread from year to year.
Brown rot infected apples on a tree
Brown rot infected apples are a source of disease
  • Fix grease bands to tree trunks to trap wingless winter moths that will be climbing the trunks to lay their eggs. This is a very effective pesticide remedy to this pest.
An apple tree with a grease band around the trunk
An apple tree with a grease band around the trunk
  • Any trained forms of fruit trees should have been summer pruned by now. So that's cordon, espalier, fan and step-over trained fruit.
  • Plant strawberry 'runners' (plants). Take care to get the planting depth right! The crown of the plant should be half in and half out after the soil settles.
A diagram showing optimum strawberry planting depth
Optimum strawberry planting depth
  • Try planting strawberries in grow-bags - a large bag will take eight plants. Leave outside until the new year, then bring into a greenhouse or polytunnel to force an early harvest.
Strawberries in a grow bag
Strawberries in a grow bag then forced for an early crop
  • Autumn fruiting raspberries should be ready to pick and are so easy to grow! These generally don't need support, and I have also found that the birds tend not to eat them!
  • Pot grown soft fruit bushes and canes will be available to buy now, but for the best value, you should place orders for bare-root plants. These will be available for planting after leaf fall. Get your soil ready for planting in the meantime; remove weeds, add compost and dig the soil over thoroughly.

Home grown vegetables and herbs

  • Make the first sowing of 'Vailan' (Winter Gem type) lettuce now. This greenhouse variety can be grown to produce tasty salads right through the winter if sown regularly and given a little heat.
  • Sow 'Winter Density' lettuce outside in the open. Cover with cloches or polythene in harsh weather.
Lettuce plants in a pot
Mixed lettuce plants in a pot
  • Sow the winter mix of Speedy Veg leaf salad leaves. This hardier mix can still be grown in the ground or containers filled with potting compost. These are perfect for window boxes or on a balcony.
  • Plant spring cabbages in well-prepared soil. Space them 30 cm (1 ft) apart. Apply a fertiliser that has low nitrogen content (nitrogen should be added in the new year). 'Hero' is a great variety to grow.
Spring cabbage 'Hero'
Spring cabbage 'Hero'
  • Lift root crops such as carrots and beetroot and store them in a frost-free location. Bury them in boxes filled with damp sand and keep them in a cool building such as a garage. Setting a mousetrap or two nearby might be a sensible precaution.
Giant beetroot
Giant beetroot
  • Lift and store potatoes in a frost-free, dark and cool place. Watch out for rodent damage in storage.
  • Plant garlic cloves. Light, well-drained soil is best so for heavier soils, plant on a ridge that has had plenty of horticultural grit added. Split the bulbs into individual cloves and plant those 20 cm (8" ) apart. Pop a handful of sand in the bottom of each planting hole to help drainage.
  • Harvest marrows, squashes and pumpkins before the first frosts. Store in a frost-free but airy shed or garage. When you cut them, leave an inch or two of stem attached.
Squash fruits
Squash fruits
  • Harvest sweetcorn when the tassels are just going brown and the top of the kernels produce a milky sap when you push in your thumbnail.
  • Sow the hardy strain of 'White Lisbon' salad onion. They will over-winter as small plants and provide you with tasty onions for early spring salads and flavouring other dishes. They will be ready well before the spring-sown salad onions are ready.
Salad onions a garden
Salad onions
  • Plant winter onion sets and banana shallots for the first crops of next summer. Try to avoid planting where they have been grown in recent years to prevent disease problems.
  • Remove yellowing leaves from the bases of cabbages, cauliflowers, sprouts, etc. Sprouts and purple sprouting may need some extra support from staking.
  • Sow more land cress, mizuna, kale and lamb's lettuce (corn salad) for winter salads. These can provide you with fresh salads for most of the winter and can be easily grown in pots and troughs too!
Mizuna and kale in rows in a vegetable garden
Mizuna and kale in rows

Soils, mulching, weed control, etc.

  • Sow empty areas of your vegetable patch with quick-growing 'green manure' crops. This will improve the soil structure and reduce nutrients being washed out of your soil by the winter rains. Choose from winter tares, grazing rye and field beans (A variety of broad bean). Dig it all into the ground before they come into flower.

Composting

  • Get compost containers ready for the autumn clean up. Construct extra or perhaps purchase new ones before the leaves start to fall.
Compost bins in a garden
Compost bins in Candide contributor Charles Dowding's garden
  • Shredders are very useful and can turn most trimmings and modest prunings into useful mulching material.
  • It's a bit early for leaves to fall but swept up leaves stuffed into black dustbin liner bags can make good compost. Make sure to punch in a few holes and leave for at least six months.
A person bagging up fallen leaves
Bagging up fallen leaves
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