GARDENERS' BOUNTY:He survived New York's Botanical Garden, so head gardener Peter Meleady is ready for anything in Dublin: organic vegetables grown in the Botanic Gardens; Florence fennel growing in the vegetable garden; alien-looking kohl rabi, which puzzles visitors, writes Jane Powers
EVERY GARDEN HAS its own miscellany of pests and diseases. Slugs and snails might be the scourge of one, blackspot and downy mildew might plague another, and wireworm and vine weevil might make life hell for the plants in yet another.
So, it comes as no surprise that the new vegetable plot at the Botanic Gardens in Glasnevin has its own set of nuisances and pathogens. The carrots, for example, have been attacked by the medieval-sounding carrot motley dwarf virus, which stunts growth and turns the leaves red and yellow.
And the pumpkin plants have also fallen victim to an anonymous yellow-streaking virus, which doesn't, however, affect their fruit- producing capabilities.
These are small annoyances in what is an otherwise healthy three-quarters of an acre of thriving edibles. Yet, there is another pest that devastates the crops, and which is especially prevalent in this garden. It's called the human being. And like all pest species, it has a sense of entitlement, helping itself to whatever takes its fancy, without caring if there's anything left after it passes through. When I visit, there is an adult male with two offspring, stripping peas and beans from plants, and plundering the produce from a prettily-arranged display cart at the garden entrance. I'd like to swat him - but what's the point, another of his ilk will be along in a minute.
In a publicly funded garden such as this, human pests are worse than ever, being of the "our taxes paid for it so we have a right to it" variety. Unfortunately, diplomacy prevents the gardeners from giving them a righteous earful. Anyway, I thought I'd mention it here, because the new vegetable garden is quite spectacular, and the sad lack of ripe tomatoes, peas and beans must be a source of frustration to the hard-working gardeners - although they are far too diplomatic to say it (but I can, so so I just did).
The gardener in charge is Peter Meleady, who arrived at the Botanic Gardens less than two years ago, and who had previously spent 13 years in the US. For much of that time he worked at the famous New York Botanical Garden in the Bronx, so he comes here with a fine and prestigious background. He manages the vegetable garden organically - a fact that makes me and a lot of other green gardeners very happy.
Imagine, our most venerable horticultural institution endorsing organic gardening, a practice that was previously the preserve of lefty loonies! My wildest dream come true.
The vegetable garden here is managed beautifully and is a showpiece of produce-growing, with everything nicely spaced, staked, pruned and organised (and with "no chemical sprays, no pesticides, and no artificial fertilisers" according to Meleady). There are at least 200 different varieties of edibles, including 10 kinds of lettuce; 13 tomatoes, both indoor and outdoor; eight potatoes; eight cabbages (and other brassicas in plenty); a heap of different pumpkins, squashes and courgettes; loads of beans and peas; great swathes of rainbow-coloured chard; beetroots, carrots, onions and sundry root crops; and an indeterminate number of other good things to eat.
A collection of Irish apples is being built up: "We're trying to get one from each county," says Meleady. Among those already settling in, are Bloody Butcher, Sheep's Snout, Yellow Pitcher and Leitrim Red. There are other Irish heirloom varieties: the gargantuan Gortahork cabbage from Donegal (traditionally used for both animal fodder and human consumption), and the very tall peas, Daniel O'Rourke and Irish Green.
Unusual vegetables such as the alien-lifeform kohl rabi and the long white Japanese daikon radish mystify some visitors, as do the courgettes that inflated into giant cudgels when supply exceeded demand, and they got left behind on the plant (interestingly, the thieves seem to shy away from the marrow family).
The soil in the walled garden where the vegetables are grown is a good free-draining loam, and slightly alkaline. Keeping it in good heart is paramount. "Feed the soil, not the plants," says Meleady, repeating the mantra of the organic movement. And accordingly, here it is fed with well-rotted cow manure, and given occasional supplementary doses of free-range poultry manure with added calcified seaweed.
Just as important as feeding the soil, is keeping it clothed. "We're trying to have as little bare soil exposed as possible. We've been using straw as a mulch, and grass clippings - which are excellent." A two-to-three-centimetre layer of freshly mown grass cuttings is thrown onto well-watered soil, where it keep weeds down, and moisture in. Grass clippings from an unfertilised lawn release about two per cent nitrogen, as well as other nutrients.
"They begin to break down and release nitrogen and other elements as soon as that they are put onto the ground. If you get them on at the beginning of the season, they will provide almost enough nutrients for the whole growing season." And, he says, you can also dig grass clippings straight into the soil (which is news to me).
The soil is also protected with green manures, crops that are allowed to reach a certain stage of maturity before being cut down and dug back in to add fertility and structure. Here, buckwheat, fodder radish and summer vetch are in full flower in the fallow beds.
The star of these cover crops, though, is the crimson clover (Trifolium incarnatum), with its dazzling, cherry-coloured, elongated flower heads. Being a member of the pea family (Papilionaceae), it adds nitrogen to the soil, but it also gives cover to predators, and attracts pollinators. Here, it is used to blanket the soil under some of the apple trees.
Intercropping and companion planting are two further organic methods practised here. Lettuces, for instance, have been planted under the bamboo bean supports, and are ready for harvest before the beans climb the poles and rob all the light.
Sunflowers are interspersed among the pumpkins, where the big, trailing foliage of the latter will form a living mulch and keep the soil moist for the former. And carrots are planted between rows of shallots and onions, which help to confuse carrot root fly, a pest that destroys entire crops of the vegetable. The fly respectfully stayed away this year, although it has been rampant in other gardens.
Birds also help control pests. A wren regularly nudges its way into the netting around the cabbages and picks off any caterpillars that it finds, while a robin keeps a beady eye out for larvae.
It's hard to believe that this flourishing patch, alive with wildlife and bouncing with produce, was bare ground just a year ago. But it was.
"Look what you can do in a season, says a happy Peter Meleady, gesturing at the delicious plenitude around him. And best bit," he says, "is that you can eat it." (But, it's best to ask first.)
jpowers@irish-times.ie
The National Botanic Gardens, Glasnevin, Dublin 9, is open daily, 9am-6pm.