The value of fleece, with Charles Dowding
By fleecing over early harvests you can keep both weather and pests at bay, says Charles Dowding
Quick and easy use of fleece covers can bring forward the date of early harvests by an impressive amount. For sure, success also relies on sowing the right seeds at the right time, and good ground preparation with few weeds, slugs and other pests. Then use horticultural fleece to keep warmth in and pests out: when allied to soil in best condition, you enjoy fantastic vegetables in May and June.
Groundwork before planting and covering
In our damp climate, it’s best to avoid undecomposed mulches because they offer habitat for slugs, and allow less of the sun’s warmth to reach the soil. They also make it difficult to sow seeds.
Early sowing and planting works best when you have spread the compost before Christmas, onto clean soil, so that winter weather softens it. Then a light raking in February or March easily breaks up any larger lumps, and disturbs/kills any early weed seedlings as they germinate.
Or if you have some top quality compost, you can spread that and sow straightaway.
Compost is dark and warms nicely in any sunshine. It looks like a black blanket over the soil and some visitors to Homeacres ask ‘why do you not mulch?’, until I explain that there is a mulch, of compost! You can sow and plant into it, the same as if it were soil.
However, if the compost is full of weed seeds, cover with fleece for two to three weeks, then remove the cover and hoe before sowing. Or, for easier gardening, set out plants - it’s easier in weedy soil to succeed with plants than direct sowings.
If your soil has couch grass, creeping buttercup and/or a mat of annual weeds, early cropping is more difficult and it’s best to use such areas for later plantings, after earlier mulching with polythene. Spread some compost or old manure before covering with polythene, to feed the soil organisms while weeds are dying. If the weeds are thick and persistent, it may be best to leave the polythene on until autumn. You can grow crops such as courgettes, squash and potatoes, planted through holes in the polythene.
Very early weed strikes, annual weeds
Most compost contains plenty of weed seeds, and many can be eliminated before sowing and planting, to save time later. Sometime in March, as soon as you see a shimmer of tiny green weed shoots, run a hoe shallowly through the compost to disturb the germinating seedlings.
Another option is to lightly pass a rake across the top, in a horizontal, sweeping motion through the compost mulch. As well as killing weed seedlings, this gives you a finer tilth on top.
Early weeds include fathen, chickweed, bittercress, groundsel, shepherds purse and annual meadow grasses. For larger weeds and any grass that is more than tiny, hand weeding is sometimes necessary. Aim for there to be no weeds visible when you sow and plant.
Gain time by raising plants
Nothing needs sowing before mid February, when light levels are increasing fast and some warmth is possible. So, between Valentine’s Day and first plantings around the equinox, a lot of growth can happen undercover. Use these timings below for southern UK, two to three weeks later for the north:
Mid February: lettuce, peas for shoots, spinach, onion, spring onion, cabbage, calabrese, kohlrabi, cauliflower, broad bean, coriander, dill, parsley.
Late February: beetroot - Boltardy only as other varieties bolt when sown this early.
Mid March: tomatoes, celeriac, celery, peas for pods and everything above.
Wait until mid April before sowing warmth-loving cucurbits and basil.
Speed up germination; plant small and deep
It’s expensive to heat air, compared to warmth below seed and module trays. The best return is from keeping warmth for germinating seeds rather than larger seedlings. Use a sunny windowsill, electric heat mat or a hotbed of fresh horse manure, say 4ft (1.2m) square.
Once seedlings are established, grow them in a non-heated greenhouse or polytunnel until ready to plant.
Planting and sowing outside
Plants can go out small, just five weeks from sowing: they look tender and vulnerable, but small transplants settle more quickly. They succeed better when set quite deep as well. When I show this to course participants they are often amazed to see my seedlings almost disappear into the compost. Plants prefer this to having their tender stems above surface level.
First outdoor sowings
Sometimes you need to wait for frost to clear, as in March 2013 when my first sowings were on April 6. Normally I sow broad beans first, then carrots and parsnips in mid March. Lay fleece over these early sowings, as described below. Also, in mid March outside, sow any of spinach, lettuce, peas, onions, early brassicas, coriander, dill and parsley, as long as your ground is slug free. Also in late March you can sow first early potatoes, followed by second earlies in mid April.
Buy 25 or 30gsm and you should be able to use the fleece again, many times: it’s no problem if there are some small holes. Fleece of 2m is wide enough for most vegetable beds, allowing room for plants to grow and push it up. It’s pleasing when you see covers rising like bubbles over your plantings.
Times of laying and removing
There is no advantage to laying a fleece cover before sowing and planting, except if you need to germinate some weeds for a hoeing. Soil’s warmth retention is slight and temporary in early spring, so the main benefit of fleece is when seeds and plants are growing.
Towards the end of April, it’s a question of when to remove covers. In 2016 we took them off later than usual in the first week of May, after most frosts and cold winds had finished. Vegetables such as courgettes benefit from fleece even in late May and June, because they dislike cold winds.
Plant out, fleece over
Save time by taking plants from your propagating area, without hardening off, and plant straightaway, even in cold weather. A fleece over the top helps plants adjust to their new environment, by protecting them from cold wind, holding warmth close to seedlings in any sun, as well as allowing some air and rain to pass through.
This way of using fleece saves time and materials - no hoops, and all you need is stones or stakes along the sides. After two to three weeks it’s a quick job to roll back the weights and flip back the cover, temporarily, for any weeding needed.
The first harvest of any vegetable is a time to savour, and these joyful moments become more frequent through spring. Picking methods such as regular removal of lettuces’ outer leaves also make harvests earlier.
Other ways to earlier harvests include planting peas for their tasty shoots, at 6in (15cm) apart: pinch off their leading shoots in early May, followed by many more harvests off the same plants, through May
Charles checks growth of pea shoots under fleece
First harvests in late April. The plantings were covered in March
April 28 last year – spinach was ready to pick that day
Fleece protecting vegetables from an April hailstorm