Try to repot an asparagus fern that has lived in the same pot for years and there’s a good chance it won’t come out. Break or cut the pot away and there is often almost no soil left at all, just a solid mass of pale, fat, finger-sized tubers wound around each other. That root ball can be split into several pieces with a bread knife, and each piece will usually grow into a new plant.
That is pretty much the asparagus fern in a nutshell. It is not a fern, it is far tougher than it looks, and most of what is interesting about it happens below the soil. Here is how to look after one. This guide covers the two you are most likely to find for sale: Asparagus setaceus (also sold as plumosa fern or lace fern, with flat, feathery sprays) and Asparagus densiflorus, which includes the arching Sprengeri type and the upright, bottlebrush-like foxtail fern (often labeled Myers or Myersii).
| Care area | What it needs |
|---|---|
| Light | Bright indirect light; a little gentle morning sun is fine |
| Water | When the top inch is dry in spring and summer; less in winter |
| Soil | Standard potting mix with some perlite or bark for drainage |
| Humidity | 40 to 60 percent; setaceus is fussier than Sprengeri |
| Temperature | 60 to 75°F; keep above about 50°F |
| Fertilizer | Half-strength balanced feed monthly in spring and summer |
| Pets | Toxic to cats and dogs; berries cause stomach upset |
Light
Asparagus ferns need more light than their delicate look suggests. Indoors, the best spot is an east window, or a few feet back from a south or west window where the plant gets plenty of brightness without hours of hot direct sun on its needles. A couple of hours of soft morning sun is welcome. The Sprengeri and foxtail types take noticeably more sun than the lacy setaceus, and outdoors in summer they can handle a fair amount if you introduce it gradually.
In low light the plant does not die quickly, but it sheds. The fine needles go pale and drop, the stems get long and sparse, and the whole thing starts to look like a tangle of green wire. If your plant is losing needles and the soil seems fine, light is the first thing to change. A grow light is a good fix for a dim room; see our picks for the best grow lights for houseplants.
Watering
From spring through early fall, water when the top inch of soil is dry, and water thoroughly until it runs out of the drainage hole. Asparagus ferns like to be evenly moist while they are actively growing, and the needles show stress quickly if the pot goes completely dry. Hanging baskets in particular can dry out in a couple of days in summer, so lifting the pot to judge its weight works better than poking the soil.
In winter, back off. The tubers store a lot of water, and in a cool room with short days the plant uses very little. Letting the top couple of inches dry between waterings is about right. Soggy soil in winter is how these plants get root rot, and it is the one mistake they do not shrug off easily.
Tap water is generally fine. These are not as sensitive to fluoride or chlorine as some houseplants.
Soil and potting
Any decent all-purpose potting mix works, with a couple of handfuls of perlite or fine bark mixed in so water drains freely. Always use a pot with a drainage hole. Plastic and glazed pots hold moisture longer, which suits the lacy setaceus; unglazed terracotta dries out faster, which can help if you tend to overwater.
Expect to repot more often than you think. Asparagus ferns multiply their tubers every year and can fill a pot completely in two or three seasons. When water runs straight through, roots poke out of the drainage hole, or white tubers start pushing up above the soil, it is time. Spring is the best season to do it. Move up one pot size, or divide the plant (more on that below).
Humidity and temperature
Normal household humidity is enough for Sprengeri and foxtail types. The lacy setaceus is fussier and will brown at the tips and shed in dry winter air, especially near a heater. Keep it away from vents and radiators, group it with other plants, and consider a small humidifier if the air in your home gets very dry. Our guide to the best humidifiers for houseplants covers a few options.
Comfortable room temperatures, roughly 60 to 75°F, suit them well. They tolerate a cool spell down to about 50°F, and a mature plant outdoors can survive a light frost by dying back to the tubers and resprouting, but indoors there is no reason to push it. Bring outdoor plants in before nights drop below 50°F, and move them into the brightest window you have, not a dim corner.
Fertilizing
A balanced liquid fertilizer at half strength once a month from spring through late summer is plenty. Asparagus ferns grow quickly in good conditions and appreciate the feed, but too much makes the stems leggy and can burn the fine roots. Skip feeding entirely in late fall and winter. If the plant is pale overall but getting good light and the right amount of water, a feeding or two usually brings the color back.
Propagation
Division is the easy way, and with a plant this size it is almost a favor to the plant. In spring, slide the root ball out of its pot. Use your hands to pull it apart where it separates naturally, or cut straight through it with a clean, sharp knife (a serrated bread knife works well on a dense clump). Make sure each piece has a good cluster of tubers and at least a few stems. Pot each section into fresh mix, water it well, and keep it in bright indirect light. Some stems may yellow for a couple of weeks while the roots settle in; new shoots usually follow.
Stem cuttings do not work. The stems will not root in water or soil, which surprises people who are used to pothos and philodendrons.
Mature plants sometimes produce small white flowers followed by green berries that ripen to red. You can sow the seeds from ripe berries, but it is slow, and division gets you a full-sized plant in a fraction of the time. One note if you live somewhere warm: both setaceus and densiflorus have become invasive in parts of Florida, Hawaii, and other frost-free places, because birds spread the berries. If your plant summers outdoors in a warm climate, pick the berries off before they ripen.
The hard reset: cutting it back to the soil
This is the most useful thing to know about this plant, and it is what makes it different from almost everything else on a windowsill. Because an asparagus fern lives in its tubers, not its stems, you can cut every single stem off at the soil line and it will grow back. Most houseplants would never forgive that. This one treats it as a fresh start.
It is the right move when a plant has gone bald and scraggly after a bad winter, when it has dropped most of its needles after a move, or when it is simply a mess of old, bare, wiry stems with a little green on the ends. Here is how to do it:
- Check the tubers first. Tip the plant out or dig gently at the edge. You want firm, pale tubers. If most of them are mushy and brown, deal with the rot first (see the common problems section below).
- Wear gloves. Many asparagus fern stems carry small hooked spines, and cutting a whole plant back means handling all of them at once.
- Cut every stem off about an inch above the soil with clean shears.
- Put the pot in bright indirect light and water a little less than usual, since there is no foliage drawing water out.
- Wait. Fresh shoots that look exactly like tiny asparagus spears usually show up within three to six weeks, and the plant is full again within a few months.
Spring and early summer are the best time, when the plant is ready to grow. A lighter version every year or two works too: cut out the oldest third of the stems at the base. The new growth that replaces them is denser and greener, and it keeps the plant from turning into a thicket of dead wood.
Common problems
Yellow needles and constant shedding are the most common complaints, and they usually come down to too little light, a sudden move, drying out, or dry winter air. Our article on why an asparagus fern turns yellow explains how to tell those apart, along with root rot and root-bound plants. Yellowing that starts at the base of the stems with wet soil points to root trouble; see root rot in houseplants. Long, sparse stems with big gaps between the needles mean the plant needs more light, much like any leggy houseplant. Spider mites and mealybugs turn up occasionally in dry rooms; a strong rinse in the shower is usually enough to clear them.
A few things people ask
Is asparagus fern toxic to cats and dogs?
Yes. The ASPCA lists it as toxic to both dogs and cats. Eating the berries can cause vomiting, stomach pain, and diarrhea, and repeated contact with the plant can cause skin irritation. Hanging it out of reach and picking off any berries is a good idea if you have pets.
Is it related to the asparagus you eat?
Yes, it is the same genus as garden asparagus. The new shoots even look like miniature spears. Do not eat them, though; the ornamental species are not grown for food, and the berries are mildly toxic to people as well.
How fast does an asparagus fern grow?
Quickly, in good light. A young plant from the garden center can double in size in a single growing season, and setaceus will start sending out long climbing stems once it is a few years old. You can trim those off at the base if you prefer a compact plant, or give them something to scramble up.
Why does my asparagus fern have thorns?
The real leaves of an asparagus fern are tiny scales on the stems, and on many plants some of those scales harden into small, curved spines. They are normal and nothing to worry about, but they are the reason gloves are worth keeping near the pot whenever you prune or repot. Next reads: Staghorn Fern Care Guide: Light, Water, and Mounting on a Board, Boston Fern Care Guide: Light, Water, and Humidity and Bird’s Nest Fern Care Guide: Light, Water, and Humidity.