Mushroom grow kit troubleshooting
Most kit problems come down to dry air, stale air or too little light. Build a humidity tent, give the kit more airflow, and move it out of a closet. If a block looks moldy or smells foul, photograph it and contact the seller before you open the bag.
Before you worry
North Spore says to focus on three things once a kit is running: hydration, airflow and light. Most problems below come back to one of them. If your kit has white fuzz, read mycelium vs mold first, because most fuzz is healthy.
Symptoms, likely causes and fixes
| Symptom | Likely cause | What North Spore suggests |
|---|---|---|
| Nothing is happening | Lion's mane mycelium is faint, so it can look inactive. The block may have been damaged in transit. The air may be too dry. | Press a damaged block back together and wait. Use a humidity tent if it is dry. |
| Pins formed, then stopped | North Spore says this is usually low humidity. | Remove the dead pins, let the block dry on a plate for about a week, soak it in cold water for 20 minutes, drain, and restart with a humidity tent. |
| Long, leggy or stringy mushrooms | Not enough airflow. | Give the kit more airflow. |
| Misshapen mushrooms | Not enough humidity. | Raise the humidity, for example with a tent. |
| Pale caps | Not enough natural light. | Keep the kit out of closets and cabinets. |
| Yellowing lion's mane | A moisture issue. | Mist from farther away. |
| Dry block after one or two flushes | The block has dried out. | Soak it. North Spore says 1 hour for oysters and 10 to 15 minutes for lion's mane. |
| Colored patches or a foul smell | Could be mold or transit damage. | Photograph it and contact the seller. See mycelium vs mold. |
How to build a humidity tent
This is the fix the seller reaches for most. North Spore recommends one for dry climates or when the AC is running.
- Use a trash bag with half-inch holes.
- Drape it over the kit.
- Mist the inside of the bag daily.
- Remove it once pins form.
If pins stopped growing
- Remove the dried-up pins.
- Rest the block on a plate for about a week.
- Soak it in cold water for 20 minutes, then drain it.
- Set up a humidity tent and mist 2 to 3 times a day.
Rootlab, another kit seller, says aborted mushrooms come from low humidity, insufficient airflow or improper lighting, which matches North Spore's advice.
When to contact the seller
North Spore says its kits are guaranteed to fruit within two weeks or it sends a replacement. Other sellers have their own terms, so read yours. If the block arrived cracked or discolored, keep the packaging and batch sticker, take a photo, and write to them before you open it. Gnats are covered in mushroom pests. The full method is in how to grow mushrooms at home.
Back to How to grow mushrooms at home
Common questions
Why is nothing happening in my mushroom kit?
North Spore lists three common causes: lion's mane mycelium that is too faint to see, a block damaged in shipping, and dry air. Press a damaged block back together, wait, and use a humidity tent if it is dry.
Why did my mushroom pins stop growing?
North Spore says it is usually low humidity. Remove the dead pins, rest the block for about a week, soak it for 20 minutes, and restart with a humidity tent.
Why are my mushrooms long and thin?
North Spore says leggy or stringy mushrooms need more airflow.
How often should I mist a grow kit?
North Spore says to spray 5 to 10 times per session, and after a soak to spray 2 to 3 times a day. It does not give a fixed schedule beyond that.
Sources
- Nothing happening in your kit, North Spore help center. Checked November 11, 2026.
- My kit produced pins but then stopped growing, North Spore help center. Checked November 11, 2026.
- Weird looking mushrooms, North Spore help center. Checked November 11, 2026.
- Spray & Grow Kit FAQ, North Spore. Checked November 11, 2026.
- Using a Spray & Grow Kit, North Spore. Checked November 11, 2026.
- Mushroom Growing Kit Problems, Tips And Tricks, Rootlab. Checked November 11, 2026.
How this page is checked
Cedrick Reese built this page from North Spore's help-center troubleshooting answers and its Spray & Grow FAQ, with one other seller's note on aborts for comparison. These are the fixes the seller gives, not our own test results. Different sellers use different blocks, so a fix that works on a North Spore kit may not suit yours, and your own kit's instructions come first.