An alocasia corm is a solid, swollen piece of stem packed with stored starch and protein, not a layered bulb like an onion.1Outside In. Unveiling Corms: Understanding Their Role in Plant Propagation A healthy one already holds the energy to grow a whole new plant in spring, as long as it gets through winter without rotting or freezing.2Outside In. Unveiling Corms: Understanding Their Role in Plant Propagation Storing it well comes down to keeping it dry, dark, and cool but never cold, with air moving around it. Alocasia tends to restart more slowly from bare-corm storage than its cousin colocasia, so many growers treat dry storage as a space-saving option rather than the default.3Ship My Plants. How to Keep Your Colocasia and Alocasia Thriving Year After Year in Co
When to Bring Alocasia In Before Winter
Night temperatures falling below 60°F are the most common trigger that sends alocasia into its winter rest, which is a stretch of dormancy when the plant stops growing and lives off what it has stored.4Plant Watering Guide. Alocasia Dormancy: How to Tell Dormant from Dying Shorter days and weaker light add to that signal.5Plant Watering Guide. Alocasia Dormancy: How to Tell Dormant from Dying New leaves stop appearing, and the existing ones shrink or yellow, oldest first. So yellowing and drooping leaves in early fall are usually the plant preparing to rest, not dying.6Houseplants Nook. Is My Alocasia Pink Dragon Dormant or Dying – Houseplants Nook Houseplants can slip into this rest too, because homes get darker and cooler in winter.7Highland Moss. Everything You Need To Know About Alocasia Dormancy
A plant still pushing out healthy new leaves during a warm spell can stay outside a little longer. Keep an eye on the forecast for the first run of nights in the 50s, and if you’re unsure, lift slightly early. That is safer than waiting through a single frost.
Frost is the hard deadline. Alocasia is a tropical plant, and freezing soil can turn its corms to mush. Dig or bring pots in after nights settle below 60°F and before your area’s average first frost date.
A light frost can blacken the leaves overnight while the corm underground seems fine, which tempts people to wait. If a surprise cold snap arrives before you are ready to dig, mulch or a cover on cold nights can buy a few days. If frost has already blackened the leaves, dig the corms soon rather than leaving them in cold, wet soil, where they are more likely to start rotting.
Whether to lift the corm at all depends on your space. Inground plants usually must be lifted, while potted ones give you a choice. Lift the corm if you lack bright indoor space for a big pot. Keep it potted if you have a cool, bright room, since restarts are faster.
Digging, Cleaning and Drying the Corms
Dig several inches out from the stem with a fork so you don’t stab the corm. Cuts and bruises are where storage rot gets in. If the soil is rock hard, water it lightly the day before, since slightly moist soil falls away from the corm more easily and with less tearing. Push the fork in a hand’s width or more from the stem and lever the soil up in a ring, working around the plant so the corm and its roots lift together. Once the clump is loose, support it from underneath and lift it out.
Pulling the plant up by its stems is the classic mistake, because it tears the corm. Cut the leaves back to a short stub of a few inches, since long stalks left attached keep sap and moisture in. Shake or rinse off the soil, but don’t scrub. Hard scrubbing removes the protective skin, and washing then storing immediately traps moisture against the corm.
Small side corms can be snapped off and stored separately as future plants. These baby corms dry out faster than the big ones, so check them more often.
Drying is the step most people skip. Let the corms air-dry in a shaded, airy, frost-free spot for about one to two weeks, until the skin feels dry and the stubs have sealed. Aroids like alocasia prefer a dry bed while dormant,8Brent & Becky’s Bulbs. Similarities & Differences Between Alocasia, Caladium, & Colocasia so a corm packed away damp is far more likely to rot. Once everything is dry, trim off the thin roots. They are brittle by then and snap away without wounding the corm.
Before storing anything, squeeze each corm. A healthy one is firm, like a raw potato. The skin may be brown and papery, which is normal, but there should be no soft, wet, or sunken patches. Discard any corm that is already mushy or foul-smelling at digging.
The Right Storage Conditions
Store corms somewhere cool and dark, the same way colocasia is commonly kept.9Ship My Plants. How to Keep Your Colocasia and Alocasia Thriving Year After Year in Co Alocasia is more tropical, though, so aim for about 50–60°F and keep it above roughly 45°F. An unheated closet, basement, or insulated garage often works. A refrigerator or a freezing garage does not.
Below about 45°F, tropical corms can suffer chilling injury, which may not show for weeks and then appears as soft, brown tissue. Much warmer storage, in the 70s, can wake corms early, so they sprout pale shoots in the dark that waste the corm’s stored energy. A steady temperature in range is better than one that swings between warm days and cold nights, because swings also cause condensation.
Check a spot with a cheap thermometer for a week before you commit. Stay away from furnaces, which dry corms out, and from exterior walls in uninsulated garages, which freeze.
Nestle the corms in dry perlite, peat, or wood shavings, and don’t water them.10Brent & Becky’s Bulbs. Similarities & Differences Between Alocasia, Caladium, & Colocasia The packing buffers humidity while still letting air reach the corm. Dry perlite is clean and holds no nutrients that mold can feed on, which makes it the lowest-risk choice for beginners. Peat and wood shavings absorb a little moisture, which helps buffer humidity, but they must be completely dry when you pack them. Avoid used potting soil or compost, since it carries organic matter and microbes that can encourage rot. Never use damp sand or moist sphagnum for winter storage. Those belong to the spring wake-up stage.
For the container, use a paper bag, cardboard box, or mesh, never sealed plastic. Corms still release a little moisture, and in plastic it condenses inside.
To set up a box, put a layer of dry packing on the bottom and space the corms so they don’t touch. Cover them lightly, and label the variety and date. Leave the lid loose or poke holes for air.
Checking for Mold and Rot Over Winter
Surface growth looks fuzzy, webby, powdery, or like a film sitting on the outside.11Alocasia Corms. Alocasia Corm Mold vs. Rot | White Fuzz Guide True rot is different: the storage tissue itself softens, turns water-soaked, collapses, or smells foul.12Alocasia Corms. Alocasia Corm Mold vs. Rot | White Fuzz Guide A firm corm with a little fuzz is usually saveable, while a soft, smelly one usually isn’t. Once a month, squeeze each corm gently for firmness, sniff the box for any sour or rotten smell, look for wet packing or condensation, and note any shrinking.
A dusting of white or gray fuzz on an otherwise firm corm usually means the air around it was too humid, not that the corm is infected throughout. Wipe it off with a dry cloth, outdoors or in a ventilated spot, since you don’t want to breathe in mold spores. Wear a mask if you are sensitive. Mold that comes back after wiping suggests the storage environment is still too damp, so fix the packing or the location. Replace any damp packing with fresh, dry material. One rotting corm can spread trouble to its neighbors, so remove it promptly.13Annals of Applied Biology. Storage rots of taro (Colocasia esculenta) in the British Solomon Islands14Annals of Applied Biology. Storage rots of taro (Colocasia esculenta) in the British Solomon Islands15Canadian Journal of Plant Pathology. Efficacy of preplant treatments of gladiolus corms with combinations of acibenzolar-S-methyl and biological or chemical fungicides for suppression of fusarium corm rot [Fusarium oxysporumf. sp.gladioli]
A corm with a small soft spot can sometimes be salvaged. Use a clean, sharp knife wiped with rubbing alcohol, so you don’t carry infection from one corm to the next. Cut until you see firm, pale tissue with no brown or water-soaked areas. If the rot reaches the center, or the corm is soft throughout, throw it out. Let the cut face dry for several days before returning it to dry packing, and keep it apart from healthy corms. Check it weekly at first, because rot that was missed can resume.
Shriveling is the opposite problem. Corms that are wrinkled but still firm are drying too much. Move them to a slightly cooler or less drafty spot. Don’t water them; extra dry packing helps hold humidity.
Keeping Alocasia as a Dormant Potted Plant
If you have room but the corm stays in its soil the whole time.16Ship My Plants. How to Keep Your Colocasia and Alocasia Thriving Year After Year in Co, bringing the pot indoors is often the easier route. Indoor winter light and cooler rooms may still push it into rest,17Highland Moss. Everything You Need To Know About Alocasia Dormancy
Keep the plant in bright indirect light and above about 60°F at night if you want it to keep growing.18Plant Watering Guide. Alocasia Dormancy: How to Tell Dormant from Dying A bright window that stays that warm gives it its best chance of staying in leaf, while a cooler spot suits one that is resting. Don’t fertilize a resting plant, since feeding a dormant corm brings no growth and can build up salts in the soil.
If it drops its leaves, water only lightly every few weeks to keep the corm from shriveling. Soggy soil around a resting corm invites the same rot as wet storage.19Brent & Becky’s Bulbs. Similarities & Differences Between Alocasia, Caladium, & Colocasia As leaves drop, the plant uses far less water. Let the top inch or two dry out before you water again, and water only until the soil just barely moistens. Make sure the pot drains freely and never leave it sitting in a saucer of water.
It can be hard to tell a dormant plant from a dying one. A dormant plant’s leaves fade but the corm stays firm. A dying one has a corm or stem base that turns soft and smelly. If you’re unsure, dig a finger down to feel the corm.
Waking Stored Corms in Spring
Begin indoors several weeks before nights stay above 60°F. First squeeze each corm. Firm ones go ahead, and slightly wrinkled but firm ones often recover once they take up moisture. Look for the small growth points, often visible as bumps on top, because they show the corm is alive and which side faces up. Discard corms that are hollow, light as paper, or soft.
Perlite is a forgiving starting medium because it holds moisture yet leaves air around new roots.20Alocasia Corms. Alocasia Corm Care Guide: 6 Ways to Sprout Corms Soaked and squeezed sphagnum moss placed loosely around the lower part of the corm keeps humidity steady, but packing moss tightly around the whole corm keeps it too wet.21Alocasia Corms. Alocasia Corm Care Guide: 6 Ways to Sprout Corms Set the corm with the growth bumps up, resting on or partly set in damp perlite, with the top uncovered. The medium should feel like a wrung-out sponge, not wet enough to drip when squeezed.
A clear or lidded container lets you see the roots and keeps humidity up. Open it for a short time every few days for fresh air. Warmth matters more than light until leaves appear, and a spot near 70–75°F speeds rooting. Roots usually appear in about 2 weeks and tiny leaves about 2 weeks later.22Sacred Elements. Everything you need to know about growing Alocasia
Over those first weeks, check the corm every few days for softness or mold, and discard it if it begins to rot. Keep the medium evenly damp, because letting it dry out stops root growth. Once leaves appear, move the container to bright indirect light so they don’t stretch and turn pale.
Pot up once there are several branching roots about 2–4 inches long.23Alocasia Corms. When to Pot Up a Sprouted Alocasia Corm: Root & Leaf Signs Waiting for about three true leaves gives a sturdier start.24Sacred Elements. Everything you need to know about growing Alocasia Use a small pot about 3–4 inches across with drainage and a chunky mix of potting soil with perlite, bark and sphagnum.25Sacred Elements. Everything you need to know about growing Alocasia Alocasia is a heavy feeder, so start feeding it once it is actively growing.26Brent & Becky’s Bulbs. Similarities & Differences Between Alocasia, Caladium, & Colocasia
Burying the corm deep in wet soil right away invites rot, and so does a pot far too big, which stays wet. Moving plants outside before nights warm sets them back.