Friday, December 28, 2012

Plan Your Asparagus Patch

A meal of fresh asparagus picked from the garden and brought into the house for a quick sauté in butter and a sprinkle with salt is one of the first signs of spring in my garden.  The first indication that anything is growing in my asparagus patch is the green spears that push through the mulch and look like the ones you buy in the grocery store.  After I pick the asparagus for about 6 weeks for my mature patch, I stop picking and allow the plants to grow.  The spears grow into 3 feet tall feathery bushes with foliage that resembles that of a very fine-leafed fern, and visitors to my garden are often mystified as to the identity of those strange plants.
Garden centers and catalogs sell seed year-round, and they sell crowns, which are dormant asparagus roots, in the late winter and early spring.  Start seeds in early spring.  Some common varieties are the heirloom “Mary Washington,” which has male and female plants, “Jersey Knight,” a hybrid with all-male plants, and “Purple Passion,” a hybrid with purple spears.  All-male plants produce bigger harvests than female plants because they do not waste energy making seeds.

Crowns, although they are the most expensive way to start asparagus, produce an asparagus harvest more quickly than plants started from seed.  Plant them as soon as you obtain them about six inches deep.  After planting and watering the crowns, cover the bed with 4 to 6 inches of mulch, leaving a small opening on top of every crown for the first tiny spears to emerge.  After the spears emerge, tuck mulch around the spears.  In subsequent years, mature plants have no trouble pushing spears through the mulch, so cover the entire bed with mulch. 

Unlike the asparagus you see in the grocery store, homegrown asparagus varies in diameter, but all tastes the same.  Harvest asparagus when it is 6 to 8 inches tall by pulling over the stalk until it snaps.  If I don’t have enough for a meal, I store spears for a few days in the refrigerator, with the ends wrapped in a moist paper towel in a closed plastic bag. 

Harvest no asparagus the first and second springs after planting if the plants were started from seed because the plant needs to devote all its energy to growing larger.  Finally, the third spring, harvest asparagus for a couple of weeks.  When the newly sprouted spears look consistently pencil-skinny, it is time to stop harvesting.  In subsequent years, harvest until the spears become skinny, usually after 6 to 8 weeks of harvest. 
Harvest a few spears the second year after planting if the plants were started from crowns, and harvest for 6 to 8 weeks in subsequent years, but stop when the spears begin to be skinny.  The remaining spears will grow into ferny little trees to adorn the garden until frost. Harvesting for longer than recommended weakens the plants.

Winter is a great time to prepare an asparagus patch.  The weather is pleasant for work, and fall leaves are available for mulch.  Asparagus is one of the easiest vegetables to grow, but planting it does require some planning since a healthy asparagus patch can produce spears for decades.  Choose a site with well-drained soil in full sun. 

Enrich the soil with compost, organic fertilizer, and lime if the soil requires it.  Eradicate any serious weed problems before planting because tilling the soil among the plants is impossible, and removing invasive weed roots from among the spears is a tedious job.  If you don’t have enough room to devote an entire bed to asparagus, mix in some plants with your perennial flowers.  Asparagus comes up at about the same time spring bulbs bloom, and the mature foliage complements flowers. 

Monday, December 10, 2012

Build a Cold Frame and Harvest Vegetables All Winter

If the cold temperatures a few weeks ago damaged your garden plants, perhaps it’s time for you to build a cold frame.  Because the runners of a nearby blackberry bush scurried under the base of the cold frame and sprouted a new plant inside the open box, and I procrastinated about removing it, I managed to plant my cold frame just before the recent cold snap.  However, the protective environment of the cold frame will cause the seeds to germinate, and I’ll soon have happy lettuces and spinach for the rest of the winter.

Unless snow falls or the temperature remains below freezing all day, which rarely happens here in SC,  I open the cover of the cold frame every morning.  Winter vegetables do not enjoy temperatures much above 70°F;  think about how easily your car heats to that temperature and beyond on an otherwise chilly day if it’s parked in the sun. 
My cold frame

My husband and I made my cold frame, which is a box covered with glass, with a discarded shower door.  Any glass or Plexiglas door or window would work; the glass allows sunshine and heat to reach the plants inside the cold frame.  If you were going to open the lid daily to allow sunlight to reach the plants, even an opaque lid would work.  The plants will be fine in the shade for a day or two if very cold weather threatens.  After you raise the lid, make sure to attach it to the ground in some way so that strong gusts of wind do not suddenly close it and shatter the glass. 

We made the sides of my cold frame out of treated lumber.  We caulked the joints and put some weather-stripping along the top of the frame to prevent drafts.  The back of the cold frame is about 18 inches high, and it slopes down to the front at about a 40-degree angle toward the southern sky; the front is about 8 inches high.  This slope is supposed to maximize the amount of captured sunlight.

If carpentry is not your forte, use stacked hay bales, concrete blocks, or landscape timbers.  My mother surrounded some of her vulnerable plants with black plastic bags full of leaves and found they provided sufficient insulation to protect them from much damage, especially if she draped a sheet of plastic over the top of the circle of bags.  Plug as many cracks as you can.

Place your cold frame directly on the ground, fill your cold frame with compost-enriched soil, and plant the seeds or transplants.  Because of the greenhouse-like moist environment, seeds sprout quickly and are the most economical choice.  Water the soil when it begins to dry out and fertilize the plants as you would in your garden. 

The best plants for a cold frame are lettuces, spinach, collards, and other cool-season greens.  Carrots, beets, and parsnips also like the protected environment.  Depending on your cold frame’s interior height, you might also be able to grow broccoli, cauliflower, and cabbage.  This winter, I am growing broccoli inside a cold frame without a lid, because it shattered in a wind gust, and I am protecting them with a sheet of plastic.

Gardening supply companies carry prefabricated cold frames; harvesting your own salad greens instead of buying them will offset the purchase price quickly.