Hornworm Care, Raising & Breeding

Hornworms are one of the most rewarding feeders you can raise at home — they grow fast, reptiles go crazy for them, and unlike a bin of roaches, a cup of bright turquoise caterpillars is something you can keep on the kitchen counter without anyone complaining. This guide covers everything I've learned about keeping hornworms alive, raising them to the size you want, and breeding your own so you never have to buy worms again. (If you want the biology behind it all, start with our hornworm life cycle guide.)

Hornworm care basics: keeping them alive

When your live hornworms arrive, they'll be in a cup with food already in the lid or base. The single most useful trick in hornworm care: store the cup with the food side up and the vented side down, so the worms climb up to eat and their droppings (frass) fall away from the food instead of piling up on it. Pop the vented lid over a paper towel every day or two and tap the frass out — a clean cup is the difference between worms that thrive and worms that die early.

Do hornworms need water? No — never add water to the cup. Hornworms get all their moisture from their food (they're about 85% water themselves). Added moisture just breeds mold, and mold is the #1 hornworm killer.

Temperature is your growth throttle:

70–80°F — full speed. A hornworm can nearly double in size every 24 hours.
55–65°F — slow motion. Use this if you have small reptiles and don't want your worms outgrowing them in a week.
Below 50°F — too cold. Unlike some feeders, hornworms can't be refrigerated; the fridge will kill them.

What do hornworms eat?

In the wild, hornworms eat tomato and tobacco plants — which is exactly why you should never feed wild-caught worms to your reptile: tobacco hornworms store the plant's toxins. Captive-bred hornworms are raised on a wheat-germ-based diet instead, which is what makes them safe (and gives them that blue-green color reptiles find irresistible).

Ours ship with enough hornworm food to reach full size, and you can buy extra if you're slowing them down or raising them from eggs. One warning from experience: once a hornworm has tasted real plant leaves, it will usually refuse the artificial diet — so keep them on the chow from day one and don't "treat" them with garden greens.

Hornworm enclosure & habitat

For a cup of 25 or fewer, the cup they ship in IS the habitat — food above, vented lid below, done. If you're raising bigger numbers (say, from hornworm eggs), set up a plastic bin with a screen or mesh section in the lid for airflow, and smear or hang the food from the top of the enclosure so the frass drops away from it, mimicking the upside-down cup. No substrate, no water dish, no misting — dry and ventilated wins every time.

Common problems (and what they actually mean)

My hornworm is shrinking and getting soft — it's not dying, it's getting ready to pupate. Don't throw it out; see the breeding section below.
Worms turning dark or black — usually too much moisture or old food. Clean the enclosure, add fresh food, and improve airflow.
Worms eating each other — hornworms only turn cannibal when they run out of food. Keep the chow ahead of them; they eat far more than you expect in the last week.
How long do hornworms live? — about 2–3 weeks of eating and growing after hatching, then pupation. Their final week is when they're at their plumpest and most nutritious as feeders.

Breeding hornworms

Breeding is where hornworms get really fun — and it saves serious money if you feed a lot of reptiles.

1. Pupation. When a worm shrinks and its dark back-line starts pulsating, it's ready. Move it to a small container with a few inches of potting soil, sawdust, or loosely crumpled paper towels — pupation needs darkness, so a lid (with air holes) helps. Its skin hardens into a dark brown puparium over about a week.

2. The wait. At room temperature, moths emerge roughly 18 days after pupation begins. Move the pupae to a screen or mesh cage before then — the moths are large (4–5" wingspan) and need room to climb and stretch their wings when they emerge.

3. Moths & eggs. Adult moths live only a couple of weeks and feed on nectar — a shallow dish of sugar water (about 1 part sugar to 4 parts water) with a paper towel wick works fine. Give them something to lay on: a live tomato plant is ideal, but many breeders get eggs on plastic leaves or even the mesh itself. Females lay small green eggs, mostly at night, and the eggs hatch in 2–5 days — and you're back at the start with free hornworms.

Not ready to run a moth cage? Skip straight to step zero: our hornworm eggs are laid within hours of your order shipping, so they hatch right when they arrive.

Get started

However you want to jump in — live hornworms with food included, hornworm eggs to raise your own, or extra hornworm food for the growing herd — everything ships fast and is backed by our Live Arrival Guarantee. Questions? Email sheller@oregonsilkworms.com — I answer everything.