September allotment garden

Last revised: 27 February 2018

Seasonal reminders, hints and tips.

Show time

Prepare your entries and entry form before the show day.

Read more about our show

Local shows

One of the premier fruit, flower and vegetable shows in Middlesex is led by the “Federation of Middlesex Horticultural and Allotment Societies”. This years show will be open to public from 2.30pm on 15th September, 2019 at Perivale Community Centre. Entrance if free. The show is worth a look to see how to present competition entries, which is just as important as quality.

Pumpkin and Squash

If the plants are not showing signs of producing fruit, try pollinating by hand. Pick a male flower and dab the stamens into female flowers. A soft brush could also be used.

Push a flower pot or short pipe, 10cm diameter or more, into the ground next to the main root. Use this to water the plant and enable the feed and water to be directed to the roots rather than leaves and emerging fruit.

Avoid watering the leaves and fruit as this promotes mildew, and any liquid feed will burn the leaves.


A spinach crop is worth sowing early in September to provide healthy greens from end of November through winter.

Spinach provides good ground cover through autumn and winter. Regular picking encourages new growth.

As the plants grow, thin them out and eat the leaves. Make room for selected plants and allow them to grow larger.


Shallots planted in spring should be ready in September. Even if the bulbs are slightly green, carefully lift the plants, clean of dirt and store in a dry place for use over next 2 or 3 months.

Potato crops

Most likely the last of the potato crop is ready to lift. Before digging, cut the haulm at soil level. Wait two weeks to allow the tuber skin to harden, which will protect them during storage.

Be sure that any diseased haulm are properly disposed of at council green recycling, and not added to your compost heap.

Green potatoes

Green potatoes contain solanine, a poisonous glycoalkaloid, which can cause a stomach upset. In most cases the tuba has grown on or near the soil surface, and being exposed to direct sunlight. High levels of solanine can cause nausea, headaches and neurological problems. Cooking does not dispel the risk.

Potatoes naturally produce small amounts of solanine as a defence against insects, but the levels increase with prolonged exposure to light and warm temperatures.

The green colour is caused by high levels of chlorophyll, which by itself is harmless. But it is also a sign that levels of solanine, which is produced at the same time as chlorophyll, have increased as well.

The greening is clear to see on tuba surface. A small patch is not likely to be significantly harmful, though an all green potato will cause harm.

In most cases of small green patches you can store sound potatoes in a dark place, and the green tinge will dissipate after a couple of weeks.

If you notice a slight green layer just under the potato skin when preparing for cooking, cut away the green portions of the potato skin before cooking and eating; there is no need to discard your favourite tuber since the non-green portion is safe to eat. However, if the tuba is showing green when cut open, discard it for safety.

Brussel Sprouts

Sprout varieties vary in height from 50 to 100cm and carry increasing weight as the buds develop. Consider staking plants to help reduce affect of wind rock and soil loosening around the roots. Earth up and firm down roots. Remove dead or dying leaves.


Pick and chop up comfrey leaves to be added to your compost heap. Although late in the year, you can make comfrey tea by using a large bucket, a quarter filled with chopped leaves and filling with water. Cover the bucket and leave in warm place. After about four weeks a smelly brown liquid will be produced. Drain of the liquid, put the leaves on the compost. The liquid can be used to feed late crops by diluting one litre to five of water.

Useful article on comfrey.

Winter Radish

A late sowing of radish can produce a crop in 10 to 12 weeks for use in October or November. Cover the initial sowing with fleece or glass to provide additional heat during cooler nights.

Fruit Trees

Check fruit trees and remove rotting fruit or foliage to the compost heap, pick up rotting fruit from the ground. The fungus and diseases will be transmitted to the good fruit or through the ground into the tree water cycle.

Green Manures

The bare ground left after taking your crops can be lightly dug over and seeded with green manure like phacelia, vetch or rye grass. These will grow quickly to provide ground cover through winter and useful mulch for digging in next spring. If weather is dry give the ground a good soak before seeding, and regular water until new shoots are showing.

More information about green manure