SO WHICH SEED-STARTING CONTAINERS REALLY WORK?

Not all seed trays are equal. We put several popular containers under the spotlight in tests to see how they influence pea root growth

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From yoghurt pots and coir cells to plastic modules and root trainers, gardeners have more seed-starting options than ever. But which containers genuinely help seedlings get off to a good start – and which ones quietly make life harder? We put a range of popular containers to the test to see how they perform in real, everyday growing conditions.

This wasn't a laboratory trial or a lesson in perfect spacing. Instead, seeds were sown much as most of us would do at home, grown indoors without added heat, and watered as needed. The aim was simple – to see how different containers affect germination, early growth and root development, and how forgiving they are when conditions aren't perfect.

HOW WE TESTED

All containers were filled with the same compost and grown indoors, using natural daylight. No bottom heat or feed was added. To reflect real gardening habits, seeds were sown at both the recommended depth (5cm) and a shallower, 'normal gardener' depth (2-3cm) in each container type.

WHAT WE TESTED

ROOT TRAINERS

Root trainers are designed to guide roots straight down and make transplanting easier, particularly for crops with strong early root growth.

Setup:

Opening/book-style root trainers

One pea per cell

Trainers placed in half trays, set inside solid trays or unheated propagator bases

Clear lids used only until germination, then removed

Results: