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Planting, Growing, and Harvesting Asparagus
Types
Female plants produce berries; males plants do not expend energy on berries so they can be up to three times more productive than female plants. For this reason, growing male asparagus plants is often preferred.
- Gardeners in Zones 4 to 6 have a wider selection of varieties, including 鈥Jersey Giant鈥, 鈥Jersey King鈥, and 鈥Jersey Knight鈥. Older varieties 鈥Mary Washington鈥 and 鈥Martha Washington鈥 may produce female plants, which are not as productive as the males.
- In colder climates, 鈥楪uelph Millennium鈥 and other varieties that emerge late often escape damage from spring freezes.
- In warmer climates, early and heat-tolerant varieties such as 鈥楢辫辞濒濒辞鈥 and 鈥UC-157鈥 produce well before the weather turns hot.
White asparagus is not a variety, but simply asparagus grown in the absence of sunlight to prevent chlorophyll from developing. White asparagus is slightly sweeter but has less fiber than green asparagus.
Purple asparagus is bred to be purple in color but turns green when it is cooked. Purple varieties tend to have thicker spears, but fewer of them. 鈥楶urple Passion鈥 is tasty but is not an all-male variety.
Harvesting
- Skip the harvest in the first year and the second year, if possible. Ideally, wait three growing seasons before harvesting in order to allow the crowns to become fully established.
- If you have young plants, the season may last 2 to 3 weeks. However, established plants produce longer鈥攗p to 8 weeks.
- Check your plant every other day for harvest-ready spears. Spears grow quickly and may become too woody before you know it! Once an asparagus spear starts to open and has foliage, it鈥檚 too tough for eating.
- Harvest spears when they reach 8 to 10 inches in height and between 1/2 and 3/4 inch thick. (Bear in mind that younger, thinner spears will be more tender, so harvest according to your own taste.)
- To harvest asparagus, simply cut the spears with a sharp knife or scissors at ground level.
- Stop harvesting spears when the diameter of the spears decreases to the size of a pencil.
- After harvest, fertilize your asparagus patch in the early summer. You can top-dress with a balanced organic fertilizer or scatter another inch of rich, weed-free compost over the decomposing mulch.
- Do NOT cut down the remaining ferns in summer or you will ruin your asparagus bed. Allow the ferns to grow and mature; this replenishes the nutrients for next year鈥檚 spear production. Always leave at least two or three spears on the plant through the growing season.
- Only cut back asparagus ferns AFTER the foliage has died back and turned brown or yellow. This is usually in early winter after several hard freezes. Cut the ferns back to the ground.
- Fertilize the bed with a 1-inch layer of rich, weed-free compost or manure topped with 3 inches of straw, rotted sawdust or another weed-free mulch. Clean spears will push up through the mulch in spring.
How to Store Asparagus
- Plunge just-cut spears into cold water immediately to preserve their sugar content.
- Asparagus does not keep for very long after it鈥檚 picked, so be sure to eat it within two or three days from harvest.
- To store, bundle the spears together, wrap the stem ends of the spears in a moist paper towel, and place the bundle in a plastic bag. Store in the crisper drawer of your refrigerator.
- If you have enough space in your fridge, you can also store asparagus by placing the spears in a cup of water. Keep about an inch of clean water in the cup.
Cooking Notes
A simple and easy favorite when it comes to asparagus is .
Catherine Boeckmann
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My asparagus plants are into their 4th year and looking ok. They are fertilized regularly and weeds kept clear of the rows. I know the soil is not the best, so I am wondering if during the fall after the ferns die I could till in some sandy loam in the rows, say 3-4 inches deep.
Asparagus is fairly tolerant to a variety of soils, but does like sandy loam. If your plants look healthy, it might not be necessary to add the loam. If you do decide to try it, however, you might set the depth at 2 to 3 inches instead, to be sure not to damage any shallow roots. Or, if you have a small enough bed, gently work the loam in at that depth with a rake or shovel. As you have indicated, the plants should be dormant when you do this. Some gardeners instead add aged manure or compost in fall, along with a layer of mulch, which will gradually improve the soil structure and health. Others might work in soil amendments in early spring, before the spears appear.
We planted asparagus crowns last year. This year I noticed a rabbit had eaten one of the spears, so to protect them I put a hoop frame over the bed. The spears are now about 24" long, and branching out. Do I just leave them or should I be doing something with them?
As they are still too young for a full harvest, and it is past harvesting stage (when spears are about 8 inches tall, and not branching), then you should, as you have suggested, just leave them to grow. Eventually they will grow tall with ferny leaf growth—too tall for the hoop frame, but at that point, perhaps the rabbits won’t be as interested in the plants. Wait until fall, after the foliage has died and browned, before cutting the ferns down to about 2 inches above the ground before winter. The leaves will help the plant make food for itself to survive over winter and grow healthy spears next year.
My asparagus is in its third year this year, should I cut off last years spears/ferns? They are about 8 inches high and fallen over due to winter
If you cut down the plants鈥 ferns last fall, leave those that appear now. You should be seeing some spears any time now, too.
My asparagus bed is four years old and I am having a problem with some of the spears being way too thin to harvest. Also, can't keep weeds from taking over bed. Heavy running rooted weeds,crabgrass? Any advice?
See the advice immediately below re fertilizer, pH, and compost to increase the size of the spears (for that matter, read the advice we give above, too).
As for the weeds, you need to pull out as many as you can and then mulch. Several inches is not too much. And 鈥渆dge鈥 the bed: Push a spade or edge into the edge of the bed to cut the weed roots there. (You’ll need to do this every year.)
I have a big asparagus bed that is over 30 years old. It still produces lots of ferns, but most of the spears are pencil-thick, and some roots seem to have died off. Every year I spread on a thick layer of compost/ seaweed. All I've read says that asparagus beds last for many years (this site says 20 or more), but none suggest what to do with an old bed. Do I dig out the old roots and start again? Leave a few plants and till deeply all around them? Abandon the site? No article has told me.
Some people would love to get pencil-thin spears!
Have you checked the pH? Asparagus likes lime. Everything you’re doing sounds good…so it might be the pH (you can get an inexpensive kit at a nursery). Digging out the roots would be a lot more work than you might think; roots could be 4 to 6 feet or more!
Then there is this (a few questions below yours): you might want to fertilize: Scatter 2 pounds of 10-20-10 fertilizer (or its equivalent) per 20 feet of row before growth begins in the spring. After the last harvest, apply an additional 1 to 2 pounds of 21-0-0 (high in nitrogen) per 20 feet. Always water the fertilizer into the soil.
With this, your plot should come back to life.
