August Gardening Calendar: Succession Planting & Green Manure

August does not mark the end of the gardening year, but an important turning point. The first major harvest wave is over, the potatoes have been dug up and the early beans picked. What remains are empty beds and soil that has performed at its best for months. Now you can set the course for autumn and the coming spring. You have two excellent options: a late harvest through succession planting or active soil care with green manure.

This August gardening calendar shows you how to make the most of the newly available space in your Garden + Outdoor area. Prepare your soil for the cold season and lay the foundations for a plentiful harvest next year.

Why is August crucial for preparing the soil for autumn?

After harvesting heavy feeders such as tomatoes, courgettes or potatoes, the soil is depleted. Important nutrients have been used up, and the soil structure may have become compacted through frequent walking on and working of the bed. If a bed is left bare, late-summer downpours wash remaining nutrients out of the upper soil layers. At the same time, pioneer weeds quickly colonise the bare ground.

August offers the perfect window of opportunity to counteract these processes. The soil is still warm, which encourages seeds to germinate. Use these favourable conditions either to grow another crop of fast-growing vegetables or to give the soil a well-deserved regenerative treatment with targeted green manure. Both options protect the soil, promote soil life and prepare it perfectly for the next season.

Green manure is practical soil protection. It feeds soil life, improves the structure and prepares the bed perfectly for the next season – an investment that pays off with every harvest.

How can you use empty beds for a second harvest (succession planting)?

The idea behind succession planting is simple: use the remaining warmth of late summer to grow vegetables with a short growing period. This allows you to harvest fresh greens from your own garden into late autumn or even winter. These plants are usually light feeders and cope well with the nutrients remaining in the soil.

Which vegetables are suitable for sowing in August?

Choose varieties that germinate and grow quickly. The days are already getting shorter, so time is a critical factor. The following crops are ideal for sowing in August:

• Lamb's lettuce: The classic autumn crop. It is hardy, frost-tolerant and germinates reliably in the warm soil temperatures of August. Do not sow it too deeply.
• Spinach: Autumn spinach grows quickly and provides a plentiful harvest before winter. Choose bolt-resistant varieties.
• Radishes: Radishes are ready to harvest in just four to six weeks. Their roots loosen the soil, and they are perfect for filling small gaps.
• Winter purslane (postelein): An often underestimated winter vegetable. It is extremely frost-hardy and can be harvested throughout the winter. Its flavour is mild and nutty.
• Asian greens: Varieties such as mizuna or pak choi grow rapidly and add a spicy note to autumn cooking. They tolerate cold weather but are not fully hardy.
• Endives and sugarloaf chicory: It is getting too late to sow these salads. Instead, buy strong young plants from a specialist retailer and plant them directly in the bed.

Preparing the bed properly for succession planting

Good preparation is the key to success. First remove all remnants of the previous crop and weed thoroughly. Then loosen the surface of the soil with a cultivator or rake. Deep digging with a spade is usually unnecessary and would disturb soil life.

Work in a thin layer of mature compost or a mild organic fertiliser. This is enough for most succession crops. The right garden tools make this job easy. Draw seed rows, sow the seeds and cover them lightly with soil. Gently firming the soil ensures good seed-to-soil contact. Then water the sown area thoroughly.

What is green manure and how does it improve your garden soil?

Green manure is a tried-and-tested method of naturally improving soil in autumn that has been used for centuries. Instead of leaving the bed empty, you deliberately sow plants that are not harvested but later worked into the soil or left on the surface as a protective layer. These “green helpers” act like a treatment for your garden soil.

A good

Green manure, green manure mix, soil specialist

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The benefits of green manure in detail

The positive effects of green manure are varied and provide long-term benefits:

• Loosening the soil: Deep-rooted plants such as oilseed radish and lupins break through compacted layers and improve air and water flow in the soil. This saves you the hard work of digging over the soil.
• Adding nutrients: Legumes such as clover, vetches and peas form a symbiosis with nodule bacteria. These bacteria bind nitrogen from the air and make it available to subsequent plants. The
  

  Persian clover 75g, green manure plant, soil improvement

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  is an excellent nitrogen fixer.
• Building humus: The biomass of green manure plants is broken down by microorganisms and converted into valuable permanent humus. Humus-rich soil can store water and nutrients more effectively.
• Suppressing weeds: A dense stand of plants shades the soil and gives weed seeds no chance to germinate. This significantly reduces the amount of weeding needed the following spring.
• Preventing erosion: Plant cover protects the valuable topsoil from becoming waterlogged and compacted by heavy rain and from being blown away by the wind.

Which plants are suitable for green manure in autumn?

Green manure plants are mainly divided into two types, depending on how they survive the winter.

Non-hardy green manure:

These plants die back during the first severe frosts. Their dead remains form a protective mulch layer on the bed, which supports soil life and keeps the soil covered. In spring, simply work the plant remains into the topsoil.

• Phacelia (bee-friendly plant): An all-rounder. It develops deep roots, suppresses weeds, is not related to our vegetable plants and provides bees with a late source of food.
• Yellow mustard: It grows extremely quickly and produces a large amount of biomass in a short time. Ideal for late sowing.
• Buckwheat: It also thrives in poorer soils and makes phosphorus available, which is otherwise difficult for other plants to access.

Winter-hardy green manure:

These plants survive the winter and continue growing in spring. They provide year-round protection for the soil. In spring, you must mow them before they flower and set seed, then work them into the soil. Allow two to three weeks before planting the new crop.

• Winter rye: It develops a substantial root system that loosens and stabilises the soil exceptionally well.
• Crimson clover: As a legume, it is an excellent nitrogen fixer.

How do you sow green manure correctly in August?

Sowing green manure is straightforward. In just a few steps, you can turn an empty bed into a green oasis for your soil.

1. Clear the bed: Carefully remove all plant remains from the previous crop and any weeds.
2. Loosen the soil: Rake over the surface of the bed to create a fine, crumbly seedbed. A broadfork or cultivator is perfect for this.
3. Sow the seeds: Scatter the seeds as evenly as possible over the entire area. Follow the quantities specified on the packaging to prevent the plants from growing too densely.
4. Lightly work them in: Rake the seeds shallowly into the top layer of soil. They should only be lightly covered with soil.
5. Firm and water: Gently pressing down with the back of the rake or a board ensures good soil contact. Then water the area thoroughly with a fine spray to avoid washing the seeds away.

Care is generally limited to watering during prolonged dry spells until the plants have formed a dense carpet. Additional garden and plant care supplies can help you look after them.

What happens to green manure in winter and spring?

How you deal with green manure in spring depends on whether you chose a frost-killed or winter-hardy variety. With frost-killed plants such as phacelia or mustard, the frost does most of the work for you. The frozen plant material remains on the bed as a protective layer.

Winter-hardy plants such as winter rye need to be actively managed in spring. Mow or cut back the growth before the plants flower and set seed. Leave the cuttings on the bed for a few days to wilt. Then work them shallowly into the soil. Wait around two to three weeks before replanting the bed. During this time, decomposition begins and the nutrients contained in the green material become available to the new plants.

Humus is the gardener’s capital. Every organic measure, from adding compost to sowing green manure, is a deposit into this account, which pays interest over the years in the form of healthy plants and reliable harvests.

August is more than just a month for harvesting. It is your opportunity to actively invest in the health of your garden. Whether you choose a late crop or soil-improving green manure, every measure that covers and nourishes the soil is a worthwhile gain. You do not end the season with empty beds, but with thoughtful preparation that will pay off handsomely in the next gardening year.

Frequently Asked Questions

What can you still sow in August?

In August, you can sow fast-growing crops such as lamb's lettuce, spinach, radishes, spring turnips and winter purslane. Lettuce varieties such as endive and sugarloaf chicory are also well suited. For soil improvement, sowing green manure plants such as phacelia or mustard is ideal for getting your beds ready for the next year.

How long does green manure need to grow?

Non-hardy green manure should grow for at least 6-8 weeks before the first frost arrives. Hardy varieties continue growing into late autumn, survive the winter and are incorporated into the soil in spring, around 2-3 weeks before the next sowing.

Is green manure better than mulching?

Green manure and mulching are two different but complementary methods. Green manure actively improves the soil from within through its roots and nutrient enrichment. Mulch protects the soil surface from drying out and erosion. Green manure that is killed by frost becomes a natural layer of mulch in winter.

Do I need to fertilise the soil before sowing green manure?

No, as a rule you don't. Green manure plants are generally undemanding. Their purpose is to bind nutrients in the soil or, in the case of legumes, even produce new nitrogen. Fertilising is therefore counterproductive and unnecessary.

Which green manure is suitable for clubroot?

If you have problems with clubroot, you should avoid brassicas such as mustard or oil radish at all costs. These can promote the disease. Instead, choose plants from other families, such as phacelia (bee-friendly), buckwheat, Persian clover or a special green manure mix without brassicas.