The middle of winter typically isn't the time to think about asparagus. At least we shouldn't think about eating it right now, since spring is the time to get delicious, fresh, local asparagus. And since you really can't get any more local than your own garden, why not start your own bed of asparagus this spring? The reason I'm thinking about it now is because there's one last thing I need to do in the garden this season, and that's to put the asparagus to bed.
Asparagus is different from most of the vegetable crops that we grow: it's a perennial, meaning that it comes back every year, unlike tomatoes or zucchini that are annual crops and have to be planted each year. In the late fall the above-ground plant dies off, but the root crowns under-ground stay alive through the winter cold. Once the soil warms up sufficiently in the spring the asparagus sends up the familiar shoots that we eat. Once you have an established asparagus bed (three years from planting) you can harvest those shoots for about 6 weeks. Why stop at 6 weeks? Well, the shoots will eventually become the leafy part of the asparagus that uses photosynthesis to make the food that ultimately winds up in the root crown underground so that the asparagus can live through the winter and send up more spears in the spring. So, sadly, there's a point where you have to stop picking the asparagus shoots, and let them grow into the tall, ferny plants that they become. This is actually a pretty nice cycle, since just at the point where you're tired of having asparagus every day, it's time to stop picking it! (This is just another example of the joy and magic of seasonal eating!)
So, how do you get started on your very own asparagus bed? The first (and most essential step) is to prepare the ground where you plan to grow your asparagus. The key thing is NO WEEDS!! (No kidding!!) Well, if you want to make your asparagus happy and your gardening life easier, no weeds would be best, or at least no perennial weeds (which include grasses, or the ever-present mugwort!) Believe it or not, it IS possible to have a pretty weed-free bed if you listen to these two words: RAISED BED! When we prepared our raised beds we spent A LOT of time digging out roots of perennial weeds like mugwort. I'm not talking rototilling here, which simply cuts the weed roots into smaller pieces that will all come back with a vengeance as vigorous new plants. I mean, dig out the roots completely and get rid of them. Once you do that, and you have the barrier a raised be can provide, your life will be much easier from here on in. (I'll post again later with more about how to establish raised beds.) The next key thing is to make sure your soil is in prime shape: get rid of any heavy clay which is ever-present in this part of the country, dig in some nice compost, add a bit of organic fertilizer for good measure, and some lime since our soils tend to be a bit acid. This is pretty much how you should prepare garden beds for anything you plant, but since your asparagus will be occupying that bed for hopefully several years to come, you want to start with the best soil you can possibly provide, and this will be your one and only chance to dig in soil amendments without disturbing those valuable root crowns.
So, now that you've prepared a wonderful bed of nice fluffy soil with lots of organic matter (compost), and fertilizer, and gotten rid of those pesky weed roots--what's next? I'd suggest you order yourself some nice, disease-free asparagus crowns. I got mine from Johnny's Selected Seeds, and I followed their directions for planting them. In the early spring plant the crowns in a trench 6-8" deep, 8-14" apart. Set aside the soil you dig out for your trench: you'll need it over the next few weeks. Lay the roots flat and cover with 1-2" of soil. As the plants grow keep adding more soil, a couple inches at a time, until you have a slight mound. Make sure you keep the patch weed-free and well-watered. The first year avoid the temptation to pick ANY of the asparagus shoots. Your new plants need to get established, so let them grow into nice tall ferns. In the fall, when the ferns have turned brown, cut them down to the ground. This will make it much easier to see and harvest the new shoots come spring. Add some more compost and/or fertilizer in the fall and again in the spring. The first year after you've planted your asparagus you can harvest a few spears, for perhaps two weeks. The third year you can harvest for the full six weeks. When you harvest you should cut all the spears (once they are 6-8" tall.) If you let some of them fern out before your harvest is finished this will attract asparagus beetles, and they'll start munching on the new spears too. Asparagus grows pretty quickly, so this means pretty much a daily harvest of a few nice spears for your dinner. Asparagus loses much of its wonderful flavor within hours after picking, so having your own bed is really the only way to truly taste what asparagus is meant to taste like. Those spears in the grocery store are likely to be a few days to a few weeks old by the time you buy them! So, enjoy your fresh harvest each spring! And don't leave it to mid-winter to cut back your asparagus plants, or you'll have cold hands like me!