Spring jobs for the garden and allotment
Posted by Dennis the Gardener on 22nd Apr 2016
Welcome to Spring everyone!
- Support pea plants with sticks, twigs, green support mesh, or wire netting.
- Thin out rows of seedlings as soon as they are large enough to be handled.
- Protect early outdoor sowings with fleece and polythene.
- Continue to force witloof chicory and seakale.
- Dig up selected chicory roots, pot them up, and position them in a dark warm place (10-13°C, 50-55°F), with and upturned pot over them.
- Prepare runner bean supports for sowing (in May) or planting out (in June).
Potatoes require an open, frost-free site with deep, fertile, moisture-retentive, friable 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 as early in April as you can with later cultivars being planted mid-April.In northerly districts and during adverse weather, little loss results from delaying 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.
Potatoes can be successfully grown in containers.
To grow outside, carry out the following steps:
- Draw a drill 7.5-15cm (3-6in) deep with a hoe or spade.
- Place tuber with the chits (sprouts) uppermost in the drill.Early cultivars should be spaced 30cm (1ft) apart in the row and 60cm (2ft) between rows.Later cultivars should be spaced 35cm (14in) apart and have 70cm (28in) between rows.
- Push the soil back over the tubers, ensuring that they are covered with at least 2.5cm (1in) of soil.
- Lightly rake over the soil surface to level it and mark the drill.
- Earth-up the plants by drawing soil around the stems to form a ridge.The final height of the ridges should be 20-30cm (8in-1ft).Earthing-up will exclude light from tubers preventing them from going green – green tubers are potentially harmful if consumed.
- Alternatively, black plastic mulch can be laid before or immediately after planting and this excludes light and suppresses weeds, so earthing-up is not required.Remember to cut a slit or cross in the plastic at each planting hole to allow the foliage to grow through.
- Protect the young growth from late frosts, either by drawing a little soil over them with a hoe or covering them with horticultural fleece.
- Some hoeing may be required to kill weeds, but earthing-up leads to the destruction of weeds and few will penetrate the foliage once it has covered the rows.
- Removal of flowers is not thought to increase yield significantly, but watering boosts yields in dry spells, especially during the critical period when tubers are forming in early summer.Thoroughly soaking potatoes every 10 days at this period ensures numerous tubers are initiated and also helps to prevent common scab disease.
- Watering in late summer may help crops bulk up and avoid second growth (see problems below).
Harvesting and storing
Lift early potatoes carefully with a fork as soon as they are ready and tubers are about the size of a hen’s egg or more.Flowering often occurs at this time, but the tubers may be ready before.Provided the crop is healthy, leave main crop plants until early to mid-autumn to bulk up (but the tubers are prone to slug damage).
For storing, lift main crop potatoes when the tops die back and the skin resists gentle pressure.All potatoes should be gathered by mid-October to avoid weather damage.
- Lift on a dry day and allow potatoes to dry on the surface of the soil for two to three hours.
- Handle tubers gently, as they bruise easily and this impairs their keeping qualities.
- Store in hessian or paper sacks or in boxes in a frost-proof shed.Avoid plastic materials, including plastic-lined paper sacks, as these promote condensation that favours early rots.
- Early and second early potatoes have a short dormant period and will sprout earlier so keep for a shorted time than the main crop cultivars.
Potatoes are generally grown from tubers known as ‘seed potatoes’.These are sprouted or ‘chitted’ prior to planting, particularly when growing early season cultivars.Chitting or sprouting tubers extends the growing period and leads to earlier tuber formation and higher yields.
- Place tubers on a tray in a single layer with the ‘rose’ end uppermost.This end has the most eyes or buds and sprouts will arise from them.Some suppliers offer ‘pre-chitted’ seed potatoes.
- Keep trays of tubers in a cool, frost-free place with moderate light, such as an unheated room and avoid direct sunlight.
- Sprouts form within a few weeks and, after about six weeks, shoots should be 5cm (2in) long and dark coloured.High temperatures and dark conditions encourage unsatisfactory pale, leggy shoots.
- Choose about four strong shoots and rub off the weaker shoots for early potatoes, but there is no need to thin for later crops.
- Tubers can be chitted from January, but planting should be delayed until March in sheltered and southern areas, or April in less favourable areas.If weather is unsuitable for planting, tubers can be left to chit further – even until May without too much crop loss.
For cultivars that are rare or old and seed potatoes are not available, micro-propagation is used to produce microplants that are strong and virus-free.These microplants are grown in the same way as seedlings in containers or outdoors when all danger of frost is past.The subsequent tubers can be eaten and some seed potatoes, saved for future cropping.
Jobs for April
Mow lawns when necessary – whenever the grass is growing – the aim is to maintain a constant height throughout the year.
Add the clippings to the compost heap in thin layers (too much grass all at once is likely to be very wet and poorly aerated, resulting in smelly slime rather than compost).
Use a half-moon edging iron or spade to create a 7.5cm (3in) ‘gutter’ around the lawn edge.This will prevent grass creeping from the lawn into borders.
Sowing new lawns or over-seeding dead patches can be carried out from mid-April to early May.If the soil is very wet or cold then germination will be poor, so delay until the weather improves.Prepare the ground for sowing, by cultivating, levelling and lightly firming beforehand.
Do not walk over or mow newly sown grass until it had reached a height of 5-7.5cm (2-3in), and then only give it a light trim at the highest setting.
Apply a high nitrogen spring lawn fertiliser at the beginning of the month to encourage good, strong growth.If moss is a problem choose a combined fertiliser and mosskiller.
April is the best month to apply weedkiller.Always follow instructions on the packaging very carefully as lawn chemicals (including fertilisers, weedkillers and mosskillers) can cause pollution of groundwater if used incorrectly.
Lightly rake lawns with a spring-tine rake to remove old plant debris.This can also be done to rake out dead moss a couple of weeks after applying a chemical moss killer.
Repair bumps and hollows by peeling back the turf, removing or adding soil, and then replacing the turf.
It is still a good time to sow a wildflower meadow, or plant wildflower plugs into existing swards.
Sowing and Planting
Hardy annuals can be sown in pots or modules to provide colour in the garden.Annual grasses can be fun to try too: Briza maxima (above image), Lagurus ovatus and Hordeum jubatum are suitable examples.In mild areas with light soil, you can sow directly outside.Marking out irregularly shaped seedbeds and broadcasting ‘drifts’ of different seed gives a more natural look.
Modular trays are useful for sowing half-hardy summer bedding plants such as marigolds (Tagetes), Lobelia, and Petunia.Label each seed tray.You will need to plant them under cover, or in a heated propagator, at the appropriate temperature, only putting them outside when the weather is reliably warm day and night.
If you started sowing early, in March or even February, you may have modules of young hardy annuals now ready for planting out.
Sweet peas can be sown outside this month.Plant out autumn-sown sweet peas that have been raised in pots, and prepare your wigwam or pea stands and supports for them to climb, using a light twine to tie the plants in.
When space becomes available in the greenhouse, pot up cuttings of tender perennials taken last summer and at the beginning of this year.Bulk up plant numbers by taking more cuttings from the largest of the new plants.
Plant summer-flowering bulbs, if you haven’t already done so.Prepare the soil first, to ensure that drainage is sufficient to prevent the bulbs rotting.Anemone coronaria tubers, for instance, need particularly well drained soils.
You can still plant herbaceous perennials such as Geranium, Astrantia (‘Burgundy Manor’) and Oriental poppies.Check that the plants you buy have strong, green shoots and plant them into well-prepared soil.
Plan a continuous crop of cut flower for this summer.Perennials such as delphiniums and annuals can be grown to produce a useful and beautiful display.
Towards the end of the month, in mild areas, you may be able to plant up your hanging baskets for the summer.
Cutting back, running and dividing
Perennials that are showing new shoots from the crown can be propagated via basel stem cuttings.Shoots 8-10cm (3-4in) high are cut from the parent plant with a sharp knife.Sometimes a piece of root can be taken with the cutting (which speeds establishment), but stems can be cut without root, and then dipped in hormone rooting powered before striking into growing medium, as for softwood cuttings.
Divide clumps of herbaceous perennials that you want to propagate, those that have become too large for their allocated space, and those that are flowering poorly or have lost their shape.Bamboos and clumps of bulbs or rhizomes can be divided in the same way.Just make sure that the transplanted divisions have roots, shoots, and are given adequate water to settle into their new positions.
Prune penstemons and other slightly tender plants such as Teucrium and Lavender.Make the cuts just above fresh, new shoots.
Some perennials benefit from having their flowering shoots thinned out.Although this results in fewer blooms, they are larger and of better quality.Delphiniums, lupins and phlox all benefit from this process.
Apply a general-purpose fertiliser to borders and beds.Take care not to damage emerging shoots, or to burn them with fertiliser.
Put supports in place for perennial before they get too large.Criss-crossing strings from hidden or decorative posts work well, allowing stems to grow up in the gaps between strings.
Remove faded daffodil and tulip flowers, nipping off the heads and seed pod at the same time.
Deadhead pansies, primulas and other spring bedding plants.Pansies will carry on into the spring and even to early summer, if attended to frequently.
Remove tired winter bedding and plants that did not survive the winter.
Check the self-seeded forget-me-nots aren’t smothering other border plants.Pull out plants if necessary.
Hoe borders to prevent annual and perennial weeds from spreading and seeding themselves.
Herbaceous perennials infested with couch grass and other perennial weeds should be lifted so the roots of the weeds can be removed.
Bulbs coming up in the rock garden or in containers may benefit from overhead protection from the raid.A sheet of glass or Perspex placed on bricks will do a good job, try to refrain from using glass where children may be near.
Top dress spring-flowering alpines with grit or gravel to show off the plants and to help prevent stem rots.Any mulches may need replacing after weed removal.
You could plant up an alpine trough to display some of your alpine plants as many can look their best at this time if year.
Check if your containers need watering.Even at this time of year, they can dry out.
Pots and tubs benefit from topping up with fresh compost.Old compost can be removed and replaced with new to a depth of 5cm (2in) if there is not much room for topping up.
Pot on plants showing signs of being pot-bound.You can tip out the root balls of unhappy looking containerised specimens, to see if they are indeed pot-bound or if they are suffering from another problem.
Jobs for the allotment in April
- Chit and plant out second early potatoes as early as possible, main crop potatoes later in April.
- Sow seed outdoors for beetroot, carrots, Swiss chard, summer cauliflower, kohl rabi, lettuce, leeks, radish, turnip, spring and pickling onions, peas and perpetual spinach in well prepared soil.
- Try sowing unusual vegetables such as salsify, Hamburg parsley, or scorzonera.
- Sow seed indoors or marrows, courgettes, pumpkins and squash.Also sweet peppers, tomatoes, cucumbers, aubergines, celery, celeriac, salads and globe artichokes.
- In very mild areas sow dwarf French beans and sweet corn outside under cloches or fleece at the end of April.In cooler areas wait until May.
- Sow a seedbed of brassicas to provide transplants of sprouting broccoli, cauliflowers and cabbages for planting out in June or July.
- Transplant broad beans grown in pots.
- Plant shallots, onion sets and garlic.
- Plant Jerusalem artichoke tubers.
- Plant asparagus crowns.
- Pot up tomato seedlings when they develop true leaves above the more rounded seed leaves.
- Apply apple and pear scab controls.
- Deal with aphids, apple sucker, pear sucker, pear midge, caterpillars and powdery mildew.
- Look out for red spider mite and aphids on strawberries under glass and treat accordingly.
- Start treating for American gooseberry mildew.
- Keep on top of weed control and continue through to summer.
- Liquid feed fruit trees in pots with a balanced feed every fortnight.
- Where possible, protect plum and pear flowers from frost but allow insect access for pollination.
- Damn down or mist citrus plants regularly when flowering begins.Maintain a min temperature of 14°C (57°F).
- Deblossom strawberries planted after September in their first year to help establishment.
- Pick forced Strawberries under heater glass.
- Ventilate strawberries under cloches and mulch with straw or mats.
- Avoid using insecticides on crops in flower.
I hope these tips add value to your gardens and allotments and you have a fantastic start to the sunshine seasons!