There are certain key times in the growing year – sometimes hours, or even just minutes – when an awful lot hinges on surprisingly little.
It might be something as simple as just forgetting to close up the polytunnel, glasshouse or cold frame on a cold late spring night before a harsh frost bites. Or taking a risky punt on planting out tender summer bedding just that teeniest bit too early. Or perhaps being just a little too slow to water trays of young seedlings on a warm, bright day. All are seemingly small oversights, errors or omissions, but ones with relatively significant consequences, proving that – as is true of so much of life – good gardening is so often all about good timing.
Few things, for example, are more disheartening than losing baby seedlings, young transplants, summer bedding and certain vulnerable species such as dahlias, delphiniums and hostas to marauding slugs and snails, something that can happen almost overnight if the right conditions (damp, cool weather) prevail. Now, as slugs and snails emerge from winter hibernation, hungry to both feed and breed, is when the risk is at its greatest.
In this case, hoping for the best is unlikely to be an effective strategy. Instead, aim to take a range of timely precautions in advance. Effective ways of minimising damage include planting into clean, weed-free soil, away from long grass or dense weedy overgrowth. Home-made liquid nettle feed applied as a foliar feed will also do a lot to help protect vulnerable plants, as will light sprinkles of organically acceptable types of slug pellets and – if the threat persists – the use of nematode control. If you have the stomach for it, then regularly hand-collecting slugs and snails at night by the light of a torch/mobile phone is yet another simple but very effective way to reduce the risk.
Damage from slugs and snails isn’t the only threat that seasoned gardeners will guard against in the weeks ahead. May, despite its special, newborn beauty, is a famously deceptive month, one when days are often balmy, but nights can be cold enough to sear or even kill new growth. The trick here is to staunchly resist being lulled into a false sense of summer by holding off from planting out cold-sensitive species until the end of the month, if possible. In the meantime, if you have young transplants under cover threatening to outgrow their pots, then consider “bumping them up” into slightly larger containers to keep them happy and healthy until they can be planted into their permanent positions outdoors.
Admittedly, this isn’t always possible. Unless you’re the proud owner of a fleet of vast polytunnels (lucky you), protected growing space is almost always at a premium at this time of year as seedlings and tender summer treasures compete for room, sometimes forcing us to make tough decisions when it comes to the process of evicting these young, vulnerable plants outdoors. If that’s the case, then prioritise the needs of any heat-loving, half-hardy and frost-tender species and baby seedlings most vulnerable to damage. If you do have to move transplants outdoors earlier than you’d like, then commit to offering them some sort of protection from the threat of low temperatures in the weeks ahead. In this case, a few warm layers of horticultural fleece or woven insulating fabrics such as Enviromesh or crop cover can be the crucial difference between life and death.
Bear in mind too that all young seedlings and transplants raised under cover of a glasshouse, polytunnel, cold frame, sunny windowsill, conservatory or porch, whether classed as tender, half-hardy or hardy, need to be toughened up, or “hardened off” in the coming weeks before being planted out into their permanent positions in the garden. This important process gradually accustoms them to the cooler, windier, more variable conditions of outdoors, protecting them against the shock of experiencing a sudden, abrupt change in their growing conditions. Ideally, it should be done over two to three weeks, starting around now.
For the first week, begin by placing plants outdoors only during the day, in a sheltered, bright spot out of direct hot sunshine and protected with several layers of horticultural fleece/Enviromesh, or crop cover, making sure to bring them in under cover again in late evening. To prevent slug and snail damage, keep these young plants off the ground on a table or bench, separated from other established outdoor potted plants that might be harbouring pests.
The following week, reduce the level of daytime protection to just one protective layer of insulating fleece/fabric. Then, in the final week, leave plants outdoors entirely, removing the protective layer during the day but replacing it late in the evening when temperatures drop. The aim here is to encourage any soft, succulent growth to gradually toughen up, making it far less susceptible to damage from cold temperatures and stiff winds, as well as pests and diseases.
Bear in mind that it’s not just home-grown seedlings and young plants that require hardening off in this way. Too many shop-bought equivalents purchased at this time of year often come straight from the artificially-protected growing conditions of a glasshouse or polytunnel. Entirely unused to outdoor growing conditions, they too will struggle to survive without first being hardened off.
[ Late-spring flowering plants can’t wait for summer to get startedOpens in new window ]
At this time of year, good timing is also crucial when it comes to taking advantage of the last window of opportunity to sow many kinds of fast-growing species of vegetables and flowering annuals. Kitchen garden varieties suitable for direct sowing outdoors in early May into weed-free, friable soil include carrots, parsnips, beetroot, spinach, turnips, peas, chard, radishes and runner beans. Varieties to sow early this month under cover into seed-trays or modules for planting outdoors next month include courgettes, pumpkins, squash, sweetcorn, French beans, Florence fennel, kale, Brussels sprouts, kohlrabi, lettuce and winter cabbage. Flowering annuals that can still be sown in early May under cover into modules or trays to give a reliable late summer display include calendula, cosmos, sunflowers, cornflowers, amaranthus, tagetes, nasturtium, cerinthe and nicotiana.
Last but not least, well-timed intervention in the shape of a few protective layers of fleece is also crucial throughout the fickle month of May in terms of protecting the delicate blossom of fruit trees and bushes from frost damage. Just one icy night can destroy the possibility of a bountiful harvest, so try to cover blossoming branches on those nights when it’s forecast. But just as importantly, make sure to remove it in the morning to allow pollinating insects access to the flowers. A bit of a faff, yes, but another good example of how a few well-timed minutes spent in the garden or allotment at this pivotal time of the growing year can pay such rich dividends down the line.
This week in the garden
Tolerant of temperatures down to -4 degrees, sweet pea plants need to get in the ground as soon as possible to give them the best chance of being properly floriferous and productive. This hardy annual species needs a sunny, sheltered spot and a fertile, moist but free-draining soil enriched with plenty of home-made compost or well-rotted manure plus some slow-release organic fertiliser. Make sure to keep young plants regularly watered until fully established.
Start thinning out rows of direct-sown vegetable seedlings to their correct spacings to prevent overcrowding and ensure strong, healthy, properly productive plants.
Dates for your diary
Festival of Gardens and Nature, Ballintubbert Gardens & House, Stradbally, Co Laois. Saturday & Sunday, May 3rd & 4th. With a host of guest speakers. festivalofgardensandnature.com.
Rare & Special Plant Fair Sunday, May 11th, Mount Congreve Gardens, Co Waterford. With up to 40 specialist nurseries from all over Ireland taking part. Admission free. mountcongreve.com
Grow Wild, the RHSI Russborough Garden Show Sunday, May 18th, Russborough House & Gardens, Blessington, Co Wicklow. With garden tours, practical demonstrations, plant stalls, and talks by guest speakers including June Blake, Kitty Scully, Paul Smyth, Rosie Maye and Danny Alvey. rhsi.ie
