Asparagus spears (Asparagus officinalis) are one of the earliest spring vegetables, but did you know that you can harvest asparagus in August as well? Even September or October if you live in a mild-enough climate. And it’s so easy to do … you just switch pruning seasons!
Traditional Spring Harvest
Usually, you start harvesting asparagus spears when they first rise out of the ground in early spring and you continue for 3 or 4 weeks, as long as the spears are still reasonably thick. When the spears become pencil thin, it’s time to stop harvesting. This allow them to expand and grow to their full size and become true leafy stems. At this point, the plant looks like a giant fern! Then you allow the stems to remain intact all summer so the plant can photosynthesize and store enough energy for next year’s crop. In other words, it essentially recharges its batteries!
Come fall, when the stems start to turn yellow, you then cut them back to the ground … and wait patiently through the winter for new spring’s crop.
By the way, you can continue to harvest this way every spring for years, as asparagus plants often live 20 years or more.
A Summer Harvest
Harvesting asparagus in summer seems surprising, but is actually practiced commercially. In fact, more and more farmers are doing it now that they realize there is a market for this “new summer crop.” It explains why you now find fresh local asparagus in August and September. And if local farmers can do it, why not you?
In the spring, harvest nothing. Not a single shoot! Leave the plant alone and allow it to grow as it wants. It will soon become tall and green, in fact, often even larger than usual, fully unfurling its airy foliage to trap a maximum of solar rays
From spring to midsummer*, let it recharge its batteries, storing ample energy reserves in its roots. Then, in mid-July, cut the plants back severely: to the ground or almost so. The plant will respond to off-season pruning by producing new shoots that will be ready to harvest in about 4 to 6 weeks. Just harvest the shoots when they reach the length you prefer. In fact, keep at it until the plant stops producing new shoots. (It will, under the shortening days of fall, simply go dormant at some point.)
*You can even force asparagus for fall or (in very mild climates) early winter crops by cutting back later still, until mid-September. After that, though, depending on your latitude, you’ll find the plants only go dormant when you prune them.
No Negative Repercussions
I know what you’re thinking: this off-season harvest must seriously harm the plant’s health and vigor, but no! Studies show that asparagus plants that were harvested in the summer are as robust and productive as those harvested in the spring and, in fact, they’re often even more robust.
My suggestion: if you have two rows of asparagus, learn to make two harvests. Put one row on the “spring harvest” regime and the other half on the “summer harvest” regime. You’ll still have about the same amount of asparagus spears each year, but with the two-crop system, you double the number of weeks when you can harvest fresh asparagus from your garden!