Everything you’re wondering about worm castings, answered straight — no jargon, no dodging, no “it depends” (okay, maybe one “it depends”).

Frequently Asked Questions

🪱 What are worm castings?

Worm castings are worm poop. Let’s just say it plainly and move on — because this is the fanciest poop in agriculture. As organic matter passes through an earthworm’s digestive tract, it gets ground up, inoculated with beneficial microbes, and coated in plant-available nutrients. What comes out the other end is a dark, crumbly, earthy-smelling material that’s part gentle fertilizer, part microbial starter culture, part soil conditioner. Nature’s slow-release multivitamin, made by worms.

🔥 Will worm castings burn my plants?

Worm castings are generally gentle and have a low salt/fertilizer-burn risk. More isn’t necessarily better, though, so following application guidelines helps you get the most value from your castings.

📏 How much should I use?

We’ve got a whole guide for this one: How Much Worm Castings Should I Use? — with exact amounts for houseplants, seedlings, vegetable gardens, trees, flower beds, and containers. The short version: a little goes a long way, and you can’t overdo it.

🌱 Can I use them on seedlings?

Absolutely — seedlings love castings. Mix them into your seed-starting medium at 10–20% by volume (about 1 part castings to 4–9 parts mix). The gentle nutrition won’t overwhelm baby roots, and the beneficial microbes help protect against damping-off, the sad disease where seedlings keel over for no apparent reason.

🪴 Can I use them on houseplants?

Yes — this is one of the best uses for castings. Top-dress each pot with 1–2 tablespoons per 6 inches of pot diameter (about ¼ cup for a big floor plant), scratch it lightly into the surface, and water normally. Repeat every 2–3 months. No repotting, no mess, no drama. Your fiddle-leaf fig has been waiting for this.

🧪 Can I use them with fertilizer?

Yes — castings play well with others. They won’t react badly with synthetic or organic fertilizers. In fact, the biology in castings helps unlock nutrients from other fertilizers, making them more available to your plants. Many gardeners find they can reduce their fertilizer use once castings are in the mix, because the soil food web starts doing more of the work. Think of castings as the teammate that makes everyone better.

🍄 Can I use worm castings with mycorrhizae?

Yes — and it’s a genuinely great pairing. Mycorrhizal fungi colonize plant roots and effectively extend the root system, trading phosphorus and water for plant sugars. Worm castings provide the organic matter, gentle nutrition, and microbial community that help those fungi establish and thrive. It’s the soil equivalent of introducing two friends who immediately become inseparable.

📦 How should I store them?

Cool, dry, and out of direct sun — a garage shelf or garden shed is perfect. Keep the bag closed but not vacuum-sealed; the microbes in castings are alive, and they appreciate a little airflow. Don’t let the bag sit in standing water, and don’t bake it in a hot car. Treat it like a living product, because it is one.

⏳ How long do worm castings last?

The mineral nutrition in castings is stable for a very long time — a year or more stored properly. The biology — the living microbes that make castings special — is liveliest in the first 6–12 months and slowly quiets down after that. Our advice: use them within a year, and buy fresh when you need more. Fresh castings are happy castings.

👃 Do worm castings smell?

Properly finished castings smell like a forest floor after rain — earthy, rich, pleasant. They should not smell like poop, ammonia, or a swamp. If your castings stink, something went wrong in the process (usually anaerobic conditions). Ours don’t. Open a bag and take a whiff — it’s the smell of healthy soil.

🔬 Are your castings tested?

Every harvest we pack gets its own lot number, and every lot has a traceable certificate. Scan the QR code on your bag (or enter the lot number on our Know Your Castings page) to pull up exactly which harvest your castings came from. Traceability first, always.

📍 Where are your castings produced?

Right here in Keystone Heights, Florida — produced in small batches from our own worm bins, raised on a diet of carefully managed bedding and food scraps. No warehouses, no mystery sourcing, no sitting in a distribution center for eight months. Small-batch means fresh, and fresh means alive.

🚚 Do you ship?

Yes! We ship using UPS to the contiguous United States. Orders are generally processed within 1–2 business days, and shipping costs are calculated based on package weight, dimensions, destination, and applicable carrier charges. Local pickup is also available in Keystone Heights, Florida.

📦 Do you offer bulk orders?

Yes! If you need larger quantities — for a farm, a nursery, a landscaping project, or a serious garden habit — get in touch with us and we’ll work out bulk pricing and logistics. We like bulk orders. Bulk orders mean big gardens, and big gardens mean a better world.

🪱 Are these castings from your own worms?

Yes. We don’t resell bulk castings under our label. We produce our own in our own worm system, in small batches, right here in Florida. The worms are employees, not contractors. They have strong opinions about watermelon rinds.

🪱 What species of worms do you use?

African nightcrawlers (Eudrilus eugeniae) — the heat-tolerant overachievers of the worm world. They thrive in Florida’s climate, process food scraps fast, and double as excellent fishing bait. (We don’t judge if you buy castings and then ask about the worms for your tackle box.)

🥬 What do you feed your worms?

A varied diet of fruit and vegetable scraps, coffee grounds, and carbon-rich bedding like shredded cardboard. No meat, no dairy, no citrus overload — we’re running a worm spa, not a garbage disposal. What goes in affects what comes out, which is why we keep their menu clean.

🌴 Are the worms raised in Florida?

Born and raised in Florida, just like the business. Our worms have never seen snow and they’d like to keep it that way. They’re acclimated to heat and humidity, which means the biology in your castings is already tuned for Florida gardens.

💧 What is the moisture level?

Our castings are moist but not wet — think “wrung-out sponge,” not “swamp.” They should feel alive and crumbly, not dusty and not dripping. We don’t publish a lab-certified moisture percentage because it varies naturally by batch and season. If your castings arrive feeling like beach sand after a light rain, that’s the sweet spot.

🧪 Do you have an N-P-K analysis?

We don’t publish a single NPK number, and here’s why: worm castings aren’t a synthetic fertilizer. Their NPK varies by batch, feedstock, and season — any single number on a bag would be a snapshot, not a promise. Castings work through biology, organic matter, and micronutrients, not just N-P-K. If you’re chasing specific numbers for a specific crop, a soil test is your best friend (and we’re happy to talk through the results).

🔍 Are the castings screened?

Yes. We harvest, screen, pack, and ship in small batches. Screening removes the big chunks and gives you a consistent, easy-to-apply product. (The worms themselves are relocated, not screened. They’re too valuable for that.)

⚡ How fresh are the castings?

As fresh as we can make them. We work in small batches — harvest, screen, pack, ship — so your castings don’t sit in a warehouse for months waiting to be discovered. Fresher castings mean more active biology. Think of it like bread: technically fine after a while, but nobody’s excited about a six-month-old baguette.

🌱 Keep growing with Living Root

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Still curious? Ask Dr. Worm — he answers reader questions right on the site and in the monthly newsletter.