Now, here’s where your patience will play an important role. Once your plants are in the ground, you can just sit back and enjoy taking care of them — for the next two to three years! Here are a few tips:
Fertilizing and watering Asparagus
Water newly established plants deeply around once a week to two weeks. Always adjust for weather and the soil condition. Never just water on a schedule, the plants can be killed if watered when already wet. Fungal and bacterial diseases can overwhelm young asparagus plants if they are watered too frequently in moist or cloudy climates.
Once established, asparagus is relatively drought tolerant and only needs infrequent, deep watering through the summer. It does need more frequent watering in dry climates with low humidity. Water asparagus before the first hard freezes in your area if there has been little rain and the soil is not moist around the asparagus bed. Don’t drown them, just give them around an inch of water to prevent them from drying out over the winter.
Make sure the plants are mulched with three to six inches of mulch at all times of the year. See the bed preparation section for more information on mulch selection.
How to fertilize the asparagus after it’s in the beds largely depends on how well-established the plants are, the size and maturity of the plants and whether you are done harvesting spears for the year. Always reference the original soil test.
Nitrogen fertilizers should be applied more heavily to plants in their first two years of growth that are still being established and aren’t being harvested. You can also use fertilizers higher in nitrogen just after you’ve finished harvesting spears on older plants to promote top growth. However, too much nitrogen applied to established plants before a harvest can cause lots of weak, fast-growing spears to form on the plants. To avoid this problem, use organic or slow-release nitrogen fertilizer such as bone meal, cottonseed meal, liquid fish or meal, or hasta gro lawn.
In general, asparagus should be fertilized with more phosphorous, and not as much nitrogen, before and during the spear harvesting. Fertilizers such as bone meal, rock phosphate, Superphosphate (NOT triple superphosphate), HastaGro plant, Mega green, etc. should work for this purpose. Use Superphosphate in alkaline soil and rock or brown phosphate in acid soil. Soft (colloidal) phosphate can be used in any soil.
If your soil test calls for potassium, use sul-po-mag, potassium sulfate, granite or greensand. You can also use muriate of potash (potassium chloride) in small quantities. Just be careful — it has lots of chlorine.