Best Propagation Trays and Plugs for Seed Starting
Seed starting is mostly about not drowning things. A tray with no drainage plus a dome plus daily watering is how most seedlings die. What works: a plug that holds air as well as water, a 1020 tray with a humidity dome you can vent, and restraint. Below are the trays, domes and plug types we stock — complete kits first, then media, trays, inserts, domes and heat — with a comparison of which medium suits which method.
Starter medium comparison
| Medium | Best for | Watch out for |
|---|---|---|
| Rockwool | Hydro, high strike rate | Must pre-soak at pH 5.5; holds a lot of water |
| Peat plugs (Rapid Rooter, Root Riot) | Beginners, soil transplant | Can dry out fast at the edges |
| Coco plugs | Coco and hydro systems | Needs Cal-Mag from the start |
| Foam (Oasis) | Cloning, commercial | pH neutral, less forgiving of overwatering |
How to choose a tray setup
- 1020 trays are the universal standard — every dome, insert and heat mat is built to fit one.
- Drainage vs no drainage. Get both: a solid outer tray and a mesh or cell insert. Bottom-watering beats top-watering for seedlings.
- Vented domes. A dome you can't vent is a mold incubator. Adjustable vents are worth the extra dollar.
- Heat mat — a root zone at 72–78°F roughly halves germination time. It's the highest-leverage cheap purchase in propagation.
What to skip
- Leaving domes on after seedlings have sprouted and hardened. They stay on too long and cause damping-off.
- Starting seeds in full-strength nutrient. Plain water until true leaves.
FAQ
Rockwool or peat plugs for seeds?
Peat plugs are more forgiving for beginners and transplant into anything. Rockwool has a higher strike rate but needs pH-adjusted pre-soaking.
Do I need a heat mat?
Not required, but root-zone heat at 72–78°F speeds germination substantially and is cheap.
How often should I water seedlings?
Bottom-water when the tray feels light, usually every 2–3 days. Daily top-watering is the most common way seedlings are killed.
Related collections
Best Cloning Machines for Beginners · Best Rooting Gels & Hormones · Best Grow Lights for Seedlings & Clones · Cloning & Seed Starting
