A lot to do before plants can brave the great outdoors

Fertile soil is key to successful sowing – but do you know how to get it, asks FIONNUALA FALLON.

THOSE OF you who started sowing seed indoors/under cover several weeks ago will now have young plants that are almost ready to be planted outdoors, but before you begin, make sure that your plants are “hardened off”.

To do this, gradually expose them to cooler temperatures by opening windows/increasing ventilation. After about a week, start bringing them outdoors during the day (for a little longer each day) – the idea is to slowly toughen them up for life in the great outdoors. The process takes about two weeks, after which they should be ready for planting. In the meantime, make a list of all the vegetables you’ve decided to grow and then try to decide their final positions in the garden.

Vegetable gardens, like the OPW’s restored walled garden at Ashtown, traditionally use a crop rotation system where plants are grown in separate groups/communities.

Ideally, each group is planted in a different part of the garden every year to prevent the spread/build up of pests/diseases and to avoid future nutrient imbalances in the soil. Perennial plants, like asparagus and artichokes, are exceptions to the rule and need a permanent position.

The five basic plant groups include the large cabbage family (everything from cauliflower and calabrese to radish and rocket); the onion family (leeks, shallots and garlic); legumes (peas, beans); umbellifers (carrots, parsnips, celeriac); and heavy feeders such as potatoes, tomatoes and courgettes.

Planning a vegetable garden this way is considered best practice, but definitely demands concentration, good research, and careful record-keeping – think of it as the horticultural equivalent of working out the seating arrangements for a large family wedding.

In small gardens, crop rotation isn't always realistic or applicable due to shortage of space. Instead, consider the popular American method of square-foot gardening, as pioneered by best-selling author Mel Bartholomew, which instead of traditional rows or drills uses a grid or matrix system of planting that divides raised vegetable beds into square feet. A different vegetable, herb or flower is planted in each square, in multiples of one, four, nine or 16 (it depends on the eventual size of the plant). Check out Bartholomew's website, www.squarefootgardening.com, for more information, or read his book All New Square Foot Gardening(available from Amazon.co.uk).

Sowing Outdoors

Now is the perfect time to begin sowing some (but not all) of your vegetable seeds outdoors, for ground temperatures are warming up nicely.

It’s also time to take a critical look at the soil in your vegetable plot, for successful seed germination outdoors requires a fertile, well-drained soil, free from weeds, well-dug and carefully raked to produce what the gardeners at Ashtown call a “fine tilth”. A fine tilth means that the soil surface is nicely crumbly, free of large stones, clods of earth, and neither too dry nor too wet.

At Ashtown, OPW gardeners Declan Donohoe, Brian Quinn and Meeda Downey have hugely improved the soil with the yearly addition of masses of manure, compost and grit, so it’s now beautifully fertile and “friable” (another nicely descriptive gardening term for crumbly soil).

If your soil is really heavy, waterlogged or compacted (often the case with new gardens), this can be hard to achieve. Use a garden fork to dig and break up the soil and remove very large stones. Leave it for a few days, then break up any remaining lumps and keep raking back and forth until you’ve achieved the right soil texture – it’s hard work but definitely oh-so-worth-it in terms of results.

If your soil is really, truly awful, don’t despair. Consider, instead, building raised beds (minimum height of 20cms) filled with well-rotted manure and imported topsoil, which are a great, productive alternative. They’re also the best option in some new gardens where unscrupulous builders have left behind only the lifeless subsoil, typically disguised beneath a uselessly shallow layer of topsoil.

Once you’ve prepared the ground for sowing, pick a nice, still day to begin work (a sudden gust of wind can blow away really fine seeds, so beware). Seed outdoors is traditionally sown in shallow drills/rows that are marked out with string held taut between two pegs/sticks.

Alternatively, consider the method of square-foot gardening as mentioned earlier. The sowing depth and spacing for seed varies hugely, depending on each vegetable, so read instructions carefully. Avoid sowing too densely or too deeply and try to sow when the soil is damp but not wet.

Very fine seed, such as carrots, can be difficult to handle while other seeds (like parsnips) have poor germination rates and need to be “station sowed” at regular intervals and in small clusters.

One clever, time-saving solution, as used by Brian and Meeda at Ashtown, is to use “seed tapes” which come with the pre-spaced seed attached to a biodegradable length of tape. Cover to the recommended depth, label (date and variety), and over the next few weeks keep a close eye out for signs of germination.

To prevent marauding slugs from devouring the young, emerging seedlings, non-organic gardeners will now often use traditional slug pellets, containing the environmentally-unfriendly and poisonous chemicals, metaldehyde or methiocarb.

At Ashtown, they use an organically-friendly slug pellet, called Ferramol, which contains only natural iron oxide. Ferramol is considered harmless to pets, birds, hedgehogs, insects and soil organisms, and is available from the Ecoshop, Greystones, Co Wicklow, www.ecoshop.ie or 01-2872914.

Other organic methods of slug-control include collecting and killing the slugs at night with boiling water (yuck), using biological controls such as nematodes (only effective at certain temperatures and in moist soil), or drowning them in beer traps (expensive but infinitely more pleasant from the slug’s point of view).

Be aware that slugs, in this respect, are like any other self-respecting beer drinkers and have a reputation for preferring the better brands, although tests have not conclusively proven this. Google “Irish craft brewer getting slugs drunk” if you want to read more on this subject and discover some of their gruesomely repellent mating rituals. Don’t, if you’re squeamish.

Planting Soft Fruit

Bare-rooted, soft fruit plants such as raspberries and strawberries should, ideally, be planted from late autumn until early spring, but like all gardeners, Declan, Meeda and Brian don’t always have the time or opportunity to do things according to schedule. The newly prepared fruit beds in the second half of the walled garden at Ashtown are only just ready for planting, and so the young, one-year-old, bare-root plants are only going in now.

“It’s obviously the wrong time of year,” admits Declan, “so fingers-crossed that they’ll be okay. We’ll be keeping a really close eye on them and making sure that they’re well-watered during the summer.”

All of the soft fruit plants at Ashtown’s walled garden come from the family-run English’s Fruit Nursery in Coonogue, Adamstown, Co Wexford.

Along with the more common types, the nursery is also supplying the gardeners at Ashtown with some unusual varieties, such as the jostaberry (pronounced yostaberry), which is a cross between a goosberry and a blackcurrant. Its fruit looks rather like a very large blackcurrant, tastes like a cross between its parents but comes without the goosberry’s painfully sharp thorns.

English’s also sell other hybrid curiosities such as the tayberry (a cross between a raspberry and a blackberry but with the taste of a loganberry), the tummelberry (hardier than the tayberry) and the boysenberry (this looks like a large raspberry but tastes more like a blackberry).

If this all sounds just too, too confusing (and I can perfectly understand if it does), then stick with more traditional types. Try strawberries – alpine varieties such as Alexandria and Mignonette are deliciously sweet and juicy, can be grown easily from seed and are ideal for small/ container gardens.

In larger gardens, grow raspberries, blackcurrants, redcurrants or gooseberries. A full colour catalogue is available from English’s Fruit Nursery at (053-92340984/9240504) and the nursery will deliver nationwide.

- Next week Urban Farmer in Property will cover how to make supports for peas and thinning seedlings outdoors

Fionnuala Fallonis a garden designer and writer