Choosing the Right Container for Planting Seeds

The One Thing That Actually Matters: Drainage Holes

Every container you use for planting seeds needs drainage holes in the base. No exceptions.

When water can't escape, it pools around the seed. Seeds need moisture, but they also need air around them and their developing roots. Sitting in waterlogged mix cuts off oxygen and creates exactly the conditions for rot — often before anything has germinated at all.

A purpose-built seed tray with blocked drainage holes is a worse choice than a recycled yoghurt tub with holes pierced in the base. The material and the price tag are irrelevant. The drainage holes are everything.

All the Options: How They Compare

Here's an honest look at the most common containers — bought and recycled — and how they actually perform for planting seeds:

The pattern is consistent: drainage determines success, not cost. A free recycled container with good drainage will outperform an expensive tray without it every time.

Can You Plant Seeds in Egg Cartons?

Yes — and they work well. Pierce a hole in the base of every cup before filling, and a cardboard egg carton becomes a genuinely useful container for planting seeds.

The cup size suits individual seeds or small clusters. Cardboard absorbs and holds moisture at a steady rate, which suits germination well. And at transplant time, there's no need to disturb the roots at all — tear off each cup and plant it directly into the ground or a larger pot. The cardboard breaks down in the soil within a few weeks.

The limitation is longevity. Cardboard softens with repeated watering and eventually falls apart — usually within three to four weeks of consistent use. Egg cartons are best suited to fast-germinating seeds that will be ready to transplant before the carton gives out. For seeds with longer germination periods, a more durable container is the better choice.

Other Recycled Containers Worth Using

Yoghurt and Takeaway Containers

Yoghurt containers are probably the most underrated option for planting seeds at home. Durable, reusable across multiple seasons, and available in a range of sizes — smaller yoghurt pots work well for individual seedlings, larger takeaway containers can be used like a shallow seed tray. Add drainage holes to the base, fill with seed raising mix, and they perform as reliably as anything purpose-built.

Containers with lids have a bonus use: during germination, the lid acts as a makeshift propagation dome, holding in warmth and moisture. Remove it as soon as seedlings appear — the same humid conditions that help seeds germinate can cause problems once they're up.

Toilet Roll Seed Pots

Toilet roll seed pots are particularly well suited to seeds that develop deep taproots early — peas, beans, sweet peas, and sunflowers. The tube gives roots room to grow straight without circling, and the open base means drainage is already sorted without any modification needed.

Stand them upright in a tray packed closely together so they support each other, fill with seed raising mix, and sow directly. At transplant time, plant the whole tube into the ground. The cardboard breaks down naturally in the soil, just like egg cartons.

They soften with repeated watering, so they're best suited to seeds that will be in the ground within three to four weeks of sowing.

Berry Punnets

Clear plastic berry punnets often have drainage holes already built into the base — check before using, and add some if not. The clear lid is useful during germination, creating a warm, humid environment that can speed things up, particularly for seeds that need warmth to strike.

Remove the lid as soon as seedlings appear. Leaving it on too long creates the conditions for damping off, a fungal problem that kills seedlings at the soil line. Once they're up, fresh air matters more than retained warmth.

Do You Need Purpose-Built Seed Trays?

Not to get started — but they're worth having once you're growing regularly.

The main advantages of purpose-built trays are consistency and durability. Cells are a uniform size, drainage is built in, and a good quality tray will last for years. If you're planting a lot of seeds at once, or want a more predictable setup, a few basic trays make the process easier and more repeatable.

They don't need to be expensive. Basic plastic seed trays from a nursery or hardware store are inexpensive and reliable. Avoid the very cheapest options — thin plastic warps when wet and cracks quickly, which defeats the purpose.

How to Fill Any Container

The method is the same regardless of what container you're using.

Fill to within about 1 cm of the rim — the small lip helps with watering and stops the mix washing over the edge. Don't pack or compress the mix down; seeds need air in the medium. Fill it, tap the container gently on the bench to settle things, and leave it at that.

Water the mix before planting seeds, not after. A pre-moistened medium gives seeds immediate contact with moisture without the risk of washing them to one side or burying them too deep. Fill, water, let it drain fully, then sow.

FAQs

Do seed trays need drainage holes?

Yes — always. Drainage holes are the single most important feature of any seed starting container, whether it's a purpose-built tray or a recycled yoghurt tub. Without them, water pools at the base and creates waterlogged conditions that cause seeds to rot before they germinate. If a tray doesn't have drainage holes, add them before use.

How many seeds should I put in each cell?

For individual cells — including egg carton cups — sow one or two seeds per cell. If both germinate, remove the weaker one by snipping it at the base with scissors rather than pulling it out, which risks disturbing the one you're keeping. For larger containers used as shallow trays, sow more freely and thin to the strongest seedlings once they're up.

Can I use a container without drainage holes if I'm really careful with watering?

Technically possible, but not worth attempting — especially for beginners. The margin for error without drainage is very small, and overwatering is already one of the most common causes of seed failure. It takes thirty seconds to add drainage holes. Just add them.

Can I reuse containers season to season?

Yes, for durable options like yoghurt tubs and purpose-built trays. Wash between uses with a diluted white vinegar solution or weak bleach to reduce the risk of carrying disease from one season to the next. Cardboard and paper containers — egg cartons, toilet rolls, newspaper pots — are single use. Compost them once seedlings are out.

What size container do seeds need?

Smaller than most people expect. Seeds don't need a lot of space to germinate — they need contact with a moist, stable medium at the right temperature. A cell around 5 cm deep and 4–5 cm wide is enough for most seeds at the germination stage. They'll need more room once they develop true leaves and are ready to move into a larger pot or the garden — but that's a transplanting decision, not a germination one.

Next Step: Watering Without Killing Them

Container sorted, seeds in the ground — the next thing most beginners struggle with is watering. How much, how often, and how to tell the difference between too wet and too dry.

If you haven't chosen a growing medium yet, that decision comes before the container:

For the complete guide from sowing to transplanting: