Peat free compost trials 2021

Over the last 6 – 7 years I’ve only used peat free compost after I switched and found my plants grew exactly the same or better in peat free compared to peat. In that time I have grown thousands of plants from seed and permanently in large pots. If the bag doesn’t clearly say ‘peat free’ it will contain peat dug from natural habitats, releasing CO2 that was locked in peat bogs into the atmosphere and reducing habitat for wildlife.

This year I’m growing everything in peat free compost as usual and I’ve been given one bag of peat to use in a series of comparison trials. I was also given the bags of Dalefoot and Sylvagrow featured here – though I’ve bought and used them for years – to trial but I’m under no obligation to say they’re good – and here you’ll see for yourself how they all perform. I will be running separate articles on each of these in the future.

This is my personal account based on how I grow, I’m being fairly scientific about it but with more resources and time, someone could conduct larger trials with multiple plants. Over time and with a number of comparisons and insights into how I grow, I hope to show you how I grow with peat free composts and why they’re such a great growing media, no matter which brand you use.

I encourage you to try the same, choose the same plant to grow in different composts but in same way, for a fair comparison.

The secret with peat free composts

One of the issues I’ve seen online is when people grow something in peat free compost and it fails, the compost is blamed. When actually, there are loads of other variables that could have caused the plant to fail such as: under or over watering, too low or too high temperatures, too little or too much fertiliser, too little or too much light, a bad batch of seeds, pests, disease, a combination of these or something else entirely.

Yet my experience is that I’ve never had a crop fail or perform badly because of the compost, whatever it is or whatever consistency or quality. And that would apply for peat composts. I’ve had crops fail of course, but for the other reasons above. One year I thought a bag of peat free had weed killer in as seedlings suddenly became stunted. But a week later they started growing again and, looking at data from our weather station, the weird growth happened in the same week as an unexpected cold snap in the weather.

Why?

It’s about understanding the growing medium. Peat compost is naturally rich in nutrient – although it too varies between product and batches – whereas home made compost and peat free composts can vary more, often with less natural immediate nutrient. Compost manufacturers try to compensate for this by adding natural of synthetic fertlisers.

Different composts will have different water retentiveness too. Peat free compost on the whole tends to be very water retentive. But it can be misleading because the top dries out faster than the rest. So with peat free compost if you aren’t checking further down, it is very easy to mistakenly overwater – something I learnt by it happening to me. I overwatered, thought there was a problem with the compost, but there wasn’t, as I found out when I tipped out the sodden plug plants.

Because peat free can have a lower nutrient content, I tend to start adding fertiliser to seedlings’ water every fortnight at half strength earlier. It changes on the plant but generally once they’ve a one or two sets of true leaves and are visibly growing strongly.

Using peat free is about learning to use compost again slightly and being more aware of plant needs, it’s not hard and once you get used to it, like me, you will find that it is better than peat. Peat dries out faster and gives you less control over the nutrient content.

Structure and texture

In reality there is very little difference between any of them. But to go into painstaking detail…

Of the four multipurpose composts I’m trialing, the peat is noticeably the finest, which may seem like a good thing but I totally disagree. I prefer growing media to be structured with small and large bits, allowing roots and water to move easily between compost, through the air spaces.

What I don’t like about super fine sand-sized composts is that over the time the structure collapses and can solidify. This is why I never intentionally use seed compost anymore, too often the tiny air gaps collapse and the seedlings struggle.

Worse is for longterm pot plantings of say 2 – 5 years where I find fine composts can – not always – compact clogging drainage. Peat free composts of mixed size, especially with bark do decompose over time and sink, compacting slightly, but keep their open airy structure for many years.

Sylvagrow Organic has the next finest with a good mix of different size pieces, but there are very few large pieces of twig etc. So it feels a balanced mix. New Horizon and Dalefoot have a similar consistency with a mix of sizes including the odd larger bit of twig or bark. Something I consider to be a good thing.

To be fair to Dalefoot, they also offer a seedling compost with a finer consistency to their multipurpose, something they recommend for seedlings. Using regular multipurpose is my preference, which is what I’m trialling here – you have both options.

Overall, I much prefer the structure of the peat free composts for both seedlings and long term plantings. I would never use such a fine compost as the peat has in long-term plantings anymore, which is also why I avoid John Innes formulas (in addition to avoiding its peat and soil content – I use soil, but from my own garden).

Round one: lettuce

6th April – sown

I asked my readers what crops / plants you’d like me to trial and something that came up from a number of you is anything with small seeds. For some reason the gardening world has convinced itself that tiny seeds need fine compost to germinate, which is wrong so in the first trial I am growing Lettuce ‘Salad Bowl’ with its tiny seeds. It’s also a fast growing leafy crop, needing reasonable amounts of nutrition.

I sowed them on 6th April as I usually do, covering ever so slightly with a dusting of compost from each and watering gently from underneath. The pots are in my unheated polytunnel.

Keep coming back to this page for updates and more rounds from different crops!

Other observations from using peat free compost

I only use peat free composts, so as well as the comparison trials, I can show you all of my other plants as they grow.

Sylvagrow Organic Peat Free Compost with 7x different types of salad leaf, beetroot and peas.

23rd March – everything germinating happily
4th April – full germination, many true leaves growing, healthy without any additional fertiliser yet.

Leave a Reply

Your email address will not be published. Required fields are marked *