Published on 06/15/01

Ugly 'Ferns' Lead to Tasty Asparagus

Photo: Wayne McLaurin

Remember, those ugly asparagus "ferns" are going to produce the tasty, big, fat, green spears that are the harbingers of spring, so fertilize, protect and encourage their growth.

The fatter, the better. Thin is not in. That's true, at least, with asparagus spears. Those little, thin spears in the store don't have the flavor the fat ones from your garden have.

What a delight that first steamed spear brings, especially if it's topped with a good Hollandaise sauce. I've known gardeners who checked their asparagus beds two or three times a day, just waiting for that first spear to pop up in the spring.

If you're lucky enough to have asparagus growing in your garden and aren't as familiar with its growth habit as you should be, you should know that asparagus is a "different animal."

The fatter your asparagus spears, the happier your plants. Pencil-thin spears indicate that either you harvested for too long during the previous season or fertility is lacking.

Eating the Stalk

When eating asparagus, you're actually eating the stalk. The leaves on the stalk, or in this case "ferns," haven't unfolded.

In the early spring, that same stalk is trying emerge and start the photosynthetic process it uses to produce carbohydrates throughout the summer and translocate back down to its root system in the fall.

You can check for this translocation by crushing an asparagus stem. If the stem has any green material (carbohydrate) left, it won't crush. But when the carbohydrates have been transferred back down to the root system, the stems will be like paper and crush easily.

Without this translocation of food, the plant won't produce spears in the spring. Wait until the ferns have turned brown and then remove and destroy them.

First to Show, Last to Go

Asparagus is one of the first vegetables showing up in the spring, and the plants should be the last ones to go out of the garden in the fall.

Unlike the case with most vegetables, we harvest asparagus during the spring and then grow the plants. Taking care of the ferns is of utmost importance in this process.

To sustain an asparagus bed, the first-year harvest should be very light. Shoots should be encouraged to grow and flourish. Fertilize according to recommendations with a 5-10-15 or 6-12-12 fertilizer in early March for most of the state.

This process builds up the root system for production next year. During the second year, harvest can be a little longer, and the third-year harvest can be normal. Weak spear production is a sign of too much harvesting the previous year.

Always leave some of the larger shoots to grow out and produce ferns.

You Must Leave the Ferns

I have heard all of the questions. "They (the ferns) are ugly. Do I really have to keep them?" "Can't I just leave a few and cut the others?" No. You must leave the ferns. Hopefully, you'll fertilize, protect and encourage their growth.

Keep a good mulch on the bed. Weeds do more damage than almost any other pest in asparagus. You can use compost, well-rotted manure or just leaves. Mulch will stimulate more even growth by keeping the asparagus roots cool, reducing weeds and adding necessary nutrients for fern growth.

Keeping the root system cool helps in building up and keeping carbohydrates. If the soil gets too hot, the plant will use energy in trying to keep cool.

Remember, "asparagus ferns" are going to produce those nice, big, fat, green spears that are the harbingers of spring.

Wayne McLaurin is a professor emeritus of horticulture with the University of Georgia College of Agricultural and Environmental Sciences.