Buying seed trays might seem simple, but choosing the wrong one can lead to poor germination, weak roots, or trays that fall apart after a single use. If you’ve had seedlings fail early or struggle during transplanting, your tray could be part of the problem. Before you start your next batch of seeds, here are five tray features that make a difference in your garden’s success.
1. Drainage Holes That Actually Work
Seeds need moisture to germinate, but too much water can cause root rot, fungal growth, or soggy soil that suffocates young roots. That’s why drainage holes are non-negotiable.
Look for trays with holes in every cell, not just a few. The holes should be large enough to let excess water escape, but not so wide that soil falls through. If your tray holds water at the bottom with nowhere to go, it’s setting your seeds up for failure.
Bonus tip: Pair your planting trays with solid bottom watering trays underneath to catch runoff. That way, your growing space stays clean and you avoid messes.
2. Cell Size and Depth That Match Your Seeds
Not all seeds are the same, and neither are their needs. That’s why cell size and depth matter more than most people realize.
Shallow trays may work for herbs and greens like lettuce, but larger seeds like tomatoes, peppers, or squash need deeper cells to grow strong roots. If the cell is too shallow, roots hit the bottom early and get cramped. Too deep, and the soil might hold excess water or make it harder for small seeds to break through.
Think about how long your seedlings will stay in the tray. If you plan to transplant quickly, smaller cells might be fine. But for more extended growing periods, give roots more space to spread and breathe.
3. Sturdy, Reusable Materials
We’ve all seen the cheap, thin trays that bend when you lift them or crack after one season. These may save a few dollars up front, but they usually don’t make it to the next growing cycle. Worse, they can collapse under pressure and ruin a tray full of carefully planted seeds.
Instead of these, look for durable, reusable seed starting trays made from BPA-free plastic, recycled materials, or heavy-duty biodegradable fiber. These hold up better to watering, handling, and the occasional bump or drop. Plus, reusing trays is good for your garden and the environment.
4. Compatibility With Domes and Bottom Trays
A great seed-starting setup includes more than just the tray. If you want consistent germination, you’ll want to use humidity domes and bottom watering systems, which means your tray needs to fit those extras.
Humidity domes keep warmth and moisture in, especially during early germination stages. Using bottom watering trays allows you to water without soaking the top layer of soil, reducing the risk of fungal diseases and helping roots grow deeper as they reach for water.
When buying trays, check the size and fit. Will they work with standard domes? Can they sit neatly inside a watering tray? A tray that doesn’t fit your other gear just adds frustration to something that should actually b enjoyable.
5. A Design That Makes Transplanting Easier
Here’s something many gardeners learn the hard way: trays that don’t let you remove seedlings easily can destroy your hard work at the finish line. If you’ve ever tried to wrestle a delicate root out of a stiff plastic tray, you know the story.
Look for features like tapered sides, flexible material, or holes at the bottom of each cell that allow you to push seedlings up from underneath gently. These small touches make a big difference when it’s time to transplant into the garden or a larger pot.
Some seed starting trays also include air-pruning designs, which help prevent root circling, facilitate separation, and strengthen overall growth.
Final Thoughts
Seed trays may seem like a small part of gardening, but they’re one of the most important tools you’ll use. Choosing the wrong one can lead to weak, overwatered, or stunted plants before they ever see the sun.
The right tray should have solid drainage, appropriate depth, durable materials, good compatibility with your setup, and a transplant-friendly design. Get those five features right, and you’ll have stronger, healthier seedlings that thrive all the way to harvest.