Best Seed Starting Kits 2026
Start seeds like a pro with the right equipment. Here's what you need for healthy, vigorous seedlings.
Essential Seed Starting Supplies
Must-Have Items
- • Seed starting trays with cells
- • Humidity domes
- • Seed starting mix (not potting soil)
- • Grow lights (or sunny window)
- • Labels and markers
Nice to Have
- • Heat mat (for warm crops)
- • Thermostat for heat mat
- • Bottom watering trays
- • Seedling fan (for stronger stems)
- • Timer for grow lights
Top Picks by Category
Best Complete Kit for Beginners
Look for: Tray, cells, dome, and basic instructions included
All-in-one kits include everything beginners need in one purchase. Look for kits with 72-cell inserts, humidity domes, and bottom trays. Add lights and heat mat separately.
Best Heavy-Duty Trays
Look for: Thick plastic, reusable for years, standard size
Flimsy trays crack after one season. Heavy-duty 1020 trays last years with proper care. Standard 10x20" size fits most shelving and dome options.
Best Heat Mat
Look for: Waterproof, fits standard trays, UL listed
Heat mats raise soil temp 10-20°F above room temperature, dramatically improving germination of warm-season crops. Get one that fits your tray size with a thermostat for best control.
Best Budget DIY Setup
Look for: Basic trays, clear plastic wrap, sunny window
On a tight budget? Basic cell packs with clear plastic wrap for humidity work. Use a sunny south window or cheap LED shop lights. Add seeds and quality seed starting mix.
What Size Cells Do You Need?
| Cell Size | Best For |
|---|---|
| 50-72 cells (small) | Herbs, lettuce, flowers - transplant early |
| 36 cells (medium) | Tomatoes, peppers, most vegetables |
| 24 cells (large) | Squash, cucumbers, melons |
| 6-12 cells (extra large) | Large transplants, extended growing time |
Frequently Asked Questions
Do I need a seed starting kit or can I use household items?
You can start seeds in egg cartons, yogurt cups, or any container with drainage. But proper seed starting trays with domes create ideal humidity and are easier to manage. Kits are worth it if you're starting more than a few seeds.
Do I need a heat mat for starting seeds?
Heat mats significantly improve germination for warm-season crops like tomatoes, peppers, and squash. Cool-season crops (lettuce, broccoli) don't need heat. If you're growing tomatoes/peppers, a heat mat is a good investment.
What's the best cell size for seed starting?
1.5" cells work for most vegetables. Large-seeded plants or those you'll grow longer before transplanting benefit from 2-3" cells. Very small seeds (herbs) can start in smaller cells.
Should I use seed starting mix or potting soil?
Seed starting mix is best - it's finer, sterile, and drains well. Regular potting soil can be too heavy, harbor disease, and crust over preventing germination. Don't skip on seed starting mix.