Beneficial Plants to Grow Near Asparagus
Asparagus is grown in a perennial bed, and it takes three to four years for the seedlings or crowns to grow a large enough underground tuber to support a crop of harvestable, springtime asparagus spears. Once established, an asparagus bed can remain productive for over a decade.
Because asparagus plants consist of a large and complex underground root system, digging deeply in the bed to plant other crops, or for weeding, can damage the asparagus roots. Whatever plants are grown with asparagus must be carefully planted as small seedlings in the spring or directly sown by seed.
Good companion plants for growing near asparagus include:
- Tomato
- Parsley
- Basil
Tomatoes are usually best grown into sturdy seedlings in the greenhouse and then transplanted into the garden into well-prepared soil. Keep tomato planting holes outside the asparagus bed, so you do not dig into the root system while preparing the soil for tomatoes.
Parsley and basil can easily be grown by seed inside the asparagus bed by sowing seeds after the final harvest of spears in June. Fertilize the bed and plant clumps of parsley and basil seeds or seedlings about 1 foot (30cm) or more away from the base of the asparagus ferns, so they are easier to pick and do not get too shaded by the mature asparagus plants.
It is important to consider the amount of shade cast by the full-grown asparagus plants, reaching between 4 and 6 feet (1.2 and 1.8 meters) in height.
Although the ferns should be cut back in late winter or early spring, for much of the year they create a large block of shade on the north side of the planting bed. Parsley, basil, and tomatoes all like plenty of sunlight, so plant them on the south side of the asparagus bed where they will not get shaded out.
Plants to Avoid Growing With Asparagus
Root and tuber crops should not be planted in or near an asparagus bed. Planting these crops would require digging into the zone occupied by the asparagus root system, and these plants have different irrigation schedules than asparagus. Avoid these plants near asparagus:
- Onions
- Garlic
- Potato
- Carrot
If you experiment with other asparagus companion planting ideas, keep in mind asparagus likes large amounts of water in summer months, little in spring, and usually needs none beyond rainfall in winter.
