Consider growing asparagus from seed

In my neighborhood, the first asparagus in spring are cheered just as much as the first snowdrops, but very quietly.

When our own have started to poke up their miraculous spears, we know the same thing is happening in other yards, most notably the ones where the owners are out of town. When these absentee gardeners return from Fiji or Umbria, their tulips will await them. But asparagus have only a moment of exquisite freshness.

Asparagus must be picked, steamed and buttered as soon as they are up, before the tips unfurl into ferny branches. They are fair game — first come, first served. After our dawn raids we might stay to pull a few of our friends’ weeds as payment.

Soon our own beds are producing so bounteously that we abandon stealth harvesting and are content with our own crop. And what a perfect crop it is, one of the few perennial vegetables. An asparagus bed, well-tended, might last half a lifetime. It’s even a landscape feature, a hedge of feathery green in summer, gold in fall. And every spring the little green missiles pop out of their underground silos with a payload of folate, fiber and vitamin C.

Such a long-term investment does require some initial labor — and patience. Asparagus needs a deeply dug bed, enriched with compost, rock phosphate and lime. Weeds and grass, especially underground menaces such as witch grass, brambles and dandelions, must be removed. A sunny spot is good, a well-drained one essential.

The standard practice is to buy asparagus crowns from a feed store, garden center or mail order nursery. A crown looks like an octopus with lots of extra tentacles. These dangling roots are spread out over a mound of enriched soil in the bottom of a shallow trench, then covered so that the top is a few inches underground.

There’s no point in planting crowns deeper; they will just work their way closer to the surface where they’d rather be anyway.

New plantings should be kept watered. An annual fall top dressing of rotted manure and/or seaweed will keep them vigorous. A summer mulch of hay, straw, chopped leaves or pine needles will help keep the soil moist and weed-free.

In recent years, more gardeners have resumed the once-common practice of starting asparagus from seed. This has always been a prudent option because it lowers the risk of bringing in diseases (though today’s varieties tend to be more resistant). It was also done so that the seedlings could be segregated in a nursery bed until they declared their sex. Asparagus are dioecious, that is they produce both male and female plants.

The females bear red berries and are fecund to a fault, producing hundreds of unwanted, weedy seedlings. Males put their energy into growing spears, and are thus more productive. The good old American varieties such as Martha Washington and Mary Washington yield plants of both sexes.

In the early 1990s, agronomists at Rutgers University developed a popular series of all-male hybrids that are good producers and don’t self-sow. Their names sound as if they might have come from Rutgers’ athletic department, or perhaps its ROTC — Jersey Giant, Jersey Knight, Jersey King, Jersey General. There also are purple varieties, such as the Italian heirloom Purple Passion. Purple asparagus is both male and female and the spears are particularly sweet and tender.

Seeds for an increasing number of varieties are now available and to me seed culture makes a lot of sense, even though people will tell you it takes longer to get a good harvest. Those roots sitting around in store bins or UPS trucks always look so tired and depleted. It’s like the difference between planting a tree as a young whip, or buying a larger, root-pruned, balled-and-burlapped specimen.

In the end, the young, healthy tree often catches up to the big one. Asparagus seeds also are more economical than crowns.

Seeds for this year should be ordered right now, as they may take a few weeks to germinate. Soak them in water for two days, in a warm spot, then plant them in soil blocks or peat pots.

Try to keep the seedlings in the 70s during the day, moving them up to larger pots and setting them out into a permanent bed after danger of frost — at least eight weeks after germination. Space them 18 inches apart in rows 4 feet apart, and plant any extras in a nursery bed in case you need to replace a few next year.

I’d wait until the third year to start sampling them, so they’ll build up their strength, and then only pick for a few weeks. By year four you can harvest for up to two months. Just keep after the weeds, pick off any asparagus beetles that show up (they’re black with orange dots or orange with black ones) and watch out for local pirates.

Barbara Damrosch

Barbara Damrosch

Barbara Damrosch’s latest book is “The Four Season Gardener’s Cookbook.”
Barbara Damrosch

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