Gardeners’ World 2021 episode 4

Gardeners’ World 2021 episode 4: It’s all about plants for free at Longmeadow this week as Monty adds self-sown ornamental grass seedlings to the paradise garden. He also divides ferns for planting elsewhere in the garden.

With the grass cutting season underway, Advolly Richmond explores the extraordinary history of lawns and some of the inventions used to achieve the perfect sward. Meanwhile, in Nottingham, we meet a gardener who discovered a passion for growing vegetables and plants when she took on an allotment.

Adam Frost finds inspiration and ingenuity when he explores the front gardens in a London street, and Joe Swift visits broadcaster and presenter Kate Garraway to find out how the garden became a sanctuary for her and her children last year.

Gardeners’ World 2021 episode 4

What is downy mildew?

Downy mildews can spoil the appearance of ornamental plants and affect the yield and quality of edible crops. Control depends on cultural techniques as no effective fungicides are available to amateur gardeners.

Downy mildew is a disease of the foliage, caused by a fungus-like (Oomycete) organism. It is spread from plant to plant by airborne spores. It is a disease of wet weather as infection is favoured by prolonged leaf wetness.

A range of common edible and ornamental plants can be affected, including brassicas, carrots, columbine (Aquilegia), foxgloves, geum, grapevines, hebe, busy Lizzie (Impatiens), lettuces, onions, pansies, parsnips, peas, poppies, rhubarb, roses, spinach and tobacco plants (Nicotiana).

Downy mildews usually have narrow host ranges comprising of just a few related plants. For example, the downy mildew affecting brassicas is a different species from the one attacking pansies.

Nasturtium – Gardeners’ World 2021 episode 4

Nasturtiums are edible flowers like marigolds, so not only do they look really colourful but they taste good too

Nasturtiums can be sown straight in the ground they are going to flower, so make sure the space where you are going to sow is weed free. Rake the soil to a fine tilth and make some drills 20mm deep. The rows should be spaced about 30cm apart. If you made a measuring stick from last month’s activities you could use this to help you.

Sprinkle the seed in carefully and cover them up with soil. As they grow, if the plants are crowded then thin them out to about 30cm apart. The petals from nasturtiums are edible and can be added to salads, they taste quite peppery and hot. Look out for our rainbow salad recipe in the summer to add your nasturtium flowers too.

Raising plants from seed

Sowing seeds indoors allows tender plants to be started off earlier in the season. When they have grown into young plants, they can be planted outside in the garden or vegetable plot once the weather is warm enough.

Many vegetables, including tomatoes and runner beans, can be started off indoors. Some, like celeriac, need a long growing season to bulk up, so are best started off indoors rather than direct outdoor sowing. See RHS Grow Your Own for advice on growing specific vegetable crops.

Annual bedding plants, such as morning glory (Ipomoea), sweet pea (Lathyrus odoratus), marigolds (Calendula and Tagetes species) and sunflowers (Helianthus cultivars) can be started off indoors to create flower displays for the summer.

Some tender perennials, such as cannas, begonias and Diascia can also be sown from seed indoors, but generally take two years to reach flowering size. Perennials live indefinitely, so a slow start pays off in the long run!

Grow your own spuds

Potatoes are a versatile vegetable that is eaten all year round. The tubers vary in size, colour, texture and taste and can be grown from spring to autumn.

Potatoes require an open, frost-free site with deep, fertile, moisture-retentive and crumbly soil for high quality and heavy yields. Improve soils by adding organic matter, such as well-rotted manure, in the autumn. Before planting, supplement with a general fertilizer, such as Growmore or blood, fish and bone, applied to the soil surface or spread along the sides of the drill during sowing, at the rate of 1kg per 10m (2.2lb per 33ft) row. Half of this amount will be enough if the garden is known to be fertile.

Once chitted (see propagation section below), seed tubers can be planted in a drill or individual holes and earthed up as they grow.

Plant early potatoes in early April, with later cultivars being planted mid-April. In northerly districts and during adverse weather, you can delay planting up to mid-May. Potato ‘seed’ tubers are also offered in late summer for a winter or Christmas crop and these can be productive in greenhouses, but planted outdoors they are vulnerable to blight disease and frost.