Although nasturtiums can take a lot of tough love, don’t be so rough with container-grown varieties. Never let them dry out, for instance. And give them a slightly shadier spot than you would in-ground plants.
Bold and brassy nasturtiums (Topaeolum majus) are true crossover plants. Best known as summer flowering annuals used to brighten up hanging baskets and beds, they are also edible. In fact, the entire plant is. But unlike many fringe foods, nasturtiums do not taste suspiciously like grass.
The youngest, juiciest leaves, which taste very much like watercress, lend a peppery zing to salads or cream cheese dip. The flowers are surprisingly spicy too, but with a shot of sweet nectar that sits in the spur. I "pickle" the green seedpods in rice vinegar and make vibrant salad dressings by steeping the colourful flowers in vinegar. Nasturtiums are good summer eating and the only way you can get them is by growing your own.
An old gardener's maxim - "Be nasty to nasturtiums; they like it" - is a good (if sadistic) reminder not to coddle this easy-to-grow plant. You'll grow the best and most abundant flowers in sunny gardens where the soil is very well draining, slightly dry and nutrient-poor. Too much nitrogen and you risk suffocating the garden (and the house, too) under Jurassic Park plants with massive, lush leaves, but you won't get any flowers.
I find it easier to get the balance of drainage and nutrition right by growing in pots. My all-time favorite is 'Empress of India,' a dwarf variety with smaller, blue-green pads and deep red flowers. It will happily grow in a small six-inch-deep pot or shallow window box. Varieties that grow in 10-to-12-inch mounds, such as 'Creamsicle' and 'Cherries Jubilee,' are also good choices for pots that are eight inches or deeper. Even deeper 12-inch pots can handle mammoth types listed as climbers or creepers. 'Moonlight' is showy yet graceful and can be trained up a wall trellis or used to cover a fence.
But don't practice cruel-to-be-kind tough love on container-grown plants. Never let them dry out, for instance. And give them a slightly shadier spot than you would in-ground plants. Alternatively, tuck them underneath the protective canopy of taller plants like tomatoes or cucumbers and let the wiry, lily-pad-shaped foliage drape over the edge of the pot.
Whether growing from seed or transplants, the best time to start nasturtiums is after all danger of frost has passed. Growing from seed is simple enough and the best way to enjoy unusual varieties that aren't available as transplants. Press the peas-sized seeds directly into the soil where you intend to grow them about one inch deep and four inches apart. You can pre-soak the seeds if you prefer, but I find unsoaked seeds germinate just the same. Treat them well (or poorly, as the case may be) and you'll find yourself flush with flowers about six to eight weeks after planting seeds. Poor care or a rambunctious disposition may be the origin of their nickname - "nasties" - or perhaps it's their penchant for attracting hoards of jittery little aphids around new leaves and flowers. Some gardeners grow nasturtiums as a sacrificial trap plant in order to protect more prized crops, pulling the entire plant out once they become infested. Since nasturtiums are a prize in themselves, I prefer to just spray the little suckers off with water as best I can and cut the plants back if the population grows out of hand. Some plants are inevitably lost by mid-summer, but I just push a few more seeds into the open space for another go before the frost drops them all dead.
Gayla Trail's new book is Grow Great Grub: Organic Food From Small Spaces. For more gardening tips, visit www.yougrowgirl.com.