What you thought of peat-free compost...

Back in February, Gardening.co.uk and Gardens Monthly magazine launched a trial calling for testers to assess the performance of peat-free compost when used to raise plants from seed. Many of the testers taking part compared the results with the same plants raised in compost containing peat. The testers raised the popular tomato variety 'Moneymaker' and a French marigold in the trial to assess how the compost performed and how the seeds grew.

We have had a very warm April this year, which is when many of the seeds were at a vulnerable stage – just pushing through the compost – so conditions were taxing.

The kit: compost, seeds and diary

Our oldest tester was possibly Frederick Thomas (aged 85) who started sowing while still recovering from a spell in hospital and was helped with the trial through further bouts of ill health by his wife. Even with these setbacks he grew 24 tomato plants and 108 French marigolds and is hoping for a good show this summer.

Adam

For tester Adam Reece from Swansea, 27 days after sowing the seeds, those in the peat-free compost had grown at half the speed of those raised in peat-based compost and looked less healthy throughout. The final numbers of plants continued to be lower in the peat-free medium.

We also received a trial diary from Saline Primary School in Fife, Scotland. The school has a garden club and along with growing wildlife-friendly plants, used the trial as part of their 'green and growing' project. The class sowed their seeds into eco-friendly pots made from rolled newspaper and kept them in the classroom – although their teacher admitted that these conditions weren't ideal and produced quite 'leggy' plants. Even so, they noticed that the plants in the peat-free compost were smaller, but the root system that developed was stronger.

Shelagh

You can read tester Shelagh Lee's account on the Forum. She was generally impressed with the peat-free compost, enough to go out and buy more to pot her other seedlings into. After pricking out, she found the marigolds in the peat-free compost looked marginally stronger than those in a proprietary compost containing peat, while the tomatoes were stronger in the compost containing peat.

Web editor Sarah B had good results with the peat-free compost and French marigolds. She found that not only did the marigold seeds germinate in the peat-free compost first, but that they also germinated in greater numbers and the subsequent plants looked sturdier overall. She noted, though, that the coarse texture of the peat-free compost seemed to be at odds with delicate seedlings (and may suit young plants better), and that the peat-free compost needed watering more often. She is now growing melons and peppers in the greenhouse in both peat-free compost and a compost containing peat.

Adam's plants fared better in compost containing peat (right tray)

Although there were individual variations between testers, the seeds sown in peat-free compost generally were slower to germinate than those sown alongside in peat-based compost. Also the number that germinated was often lower, although not all testers recorded specific numbers.Reduced germination was more marked in the tomato seeds than the French marigolds (which are notoriously quick and easy to germinate). For one or two testers, the tomatoes seeds failed to germinate significantly and they had to consider whether the seed was at fault, especially as a second sowing with a different variety proved more successful. This may be because the testers were more familiar with the compost characteristics second time around.

Interestingly, once the seeds had grown to a size for pricking out or planting into pots, those grown in the peat-free compost generally caught up or developed into sturdier plants.

Many testers were happy with the peat-free compost once they had got used to how it performed differently to alternatives containing peat, while one or two felt that the extra work involved in using peat-free compost was only worth it for the benefit to the environment. For some testers the results were disappointing and they are not prepared to use this compost again.