Starting from seed is the cheapest way to fill a greenhouse or garden — and the most rewarding. Get four things right (a tray, warmth, light and the right medium) and you'll grow healthier plants than most transplants you can buy.
Germination needs consistent warmth and moisture; seedlings then need bright light to stay stocky. A sturdy tray with a humidity dome on a heat mat handles the first; a T5 or small LED handles the second. The medium ties it together.
A quick map of the options before you spend.
| Item | Job | Look for | Price tier |
|---|---|---|---|
| Trays / inserts | Hold cells of medium | Heavy-duty (reusable) 1020 | $ |
| Humidity dome | Traps moisture for germination | Adjustable vents | $ |
| Heat mat | Warms medium to speed sprouting | Built-in or add-on thermostat | $ |
| Growing medium | Light, airy seed mix | Fine seed-start mix or coir | $ |
| Seedling light | Prevents leggy growth | T5 LED / small board | $$ |
The best tray and the brightest light can't fix weak genetics. Wherever you grow — and where it's legal to do so — starting from reputable, viable seed makes everything downstream easier. Two seed sources growers rate highly:
Grow only what is legal in your jurisdiction. Always check your local laws before purchasing or planting seed.
Established product lines we'd point a friend to. Specs are typical figures — always confirm the current listing.
Flimsy trays crack after one season — heavy-duty 1020 trays last for years. Bootstrap Farmer is the durability benchmark; pair open flats with cell inserts to suit your seeds.
Bottom heat dramatically speeds and evens germination. A mat with a thermostat lets you hold the ideal medium temperature. VIVOSUN heat mats are a popular, affordable choice.
The simplest start: tray, cells and a vented humidity dome in one box. Great for first-timers — just add medium, seed and light. Burpee and Jiffy make reliable kits.
Garden soil is too dense and risky for seeds. A fine, sterile seed-starting mix or coco coir gives the light, airy, disease-free root zone seedlings need to thrive.
Count back from your last expected frost date. Many warm-season crops are started indoors roughly 6–8 weeks before that date, so they're stocky transplants ready to go out when it warms up. Each plant differs — check the seed packet — but starting indoors under lights buys you weeks of extra season.
That's 'legginess', and it's almost always too little light. Seedlings on a windowsill stretch toward weak light and topple. The fix is a bright light placed just a few inches above the tray, like an inexpensive T5 strip. Gentle airflow from a small fan also strengthens stems.
Not for everything, but it helps a lot. Many seeds germinate faster and more evenly with consistent bottom warmth, and some warm-season crops barely sprout without it. A heat mat with a thermostat is one of the best-value seed-starting upgrades you can make.
Reuse heavy-duty trays for years — just rinse and, if disease was an issue, sanitise them between batches. Don't reuse spent seed-starting medium for new seeds, as it can harbour disease and loses structure; compost it into the garden instead and start fresh.