Comparing New Horizon and SylvaGrow

The society sold New Horizon general purpose compost at the Trading Hut for 20 years. Back in 2000 it was almost the only peat-free compost available. In 2020 we started stocking another brand, SylvaGrow, instead of New Horizon, so I wanted to compare these peat-free composts.

Trialled here are New Horizon All Vegetable compost and Sylvagrow Multi-Purpose compost.

Pictured below are grafted tomato seedlings received by post and planted into identical pots on 14th April, and placed on a south-facing window sill.

The four plants on the left are in New Horizon, those on the right are in Sylvagrow. I have swapped the two trays over every few days to ensure that each batch gets a similar amount of light. I have watered so as to keep the compost moist in each pot. After 20 days the SylvaGrow batch shows considerably stronger growth: the plants are double the height, they have more leaves, and their stem diameter is about 50% greater than the New Horizon batch.

Conclusion

It’s very clear: my tomato seedlings have performed much better so far in SylvaGrow than in New Horizon.

Further info

The plants here are the Crimson Collection from Chase Organics, each batch of 4 plants comprising 1 each of Crimson Crush, Crimson Blush etc. I bought two batches for £13.99 so these grafted plants cost £1.75 each.

I have potted up some other (ungrafted) tomato varieties in the same way: half each in the two brands of compost. They are all younger and smaller than the Crimson Collection at the moment, but I will have more examples to compare as they grow.

The two compost products seem to have similar ingredients but it is not entirely clear, because the info on the New Horizon sack uses marketing terms whereas SylvaGrow simply states what its ingredients are.

The particle size is larger in New Horizon than in SylvaGrow. The New Horizon compost does not hold water as well as SylvaGrow. Perhaps this is the reason for the performance difference: it dries out quicker, and when it is dry, water drains straight through.

New Horizon also do a product specifically for tomatoes which I have not tried yet.

A word about peat and composts: please don’t buy any product containing peat.

Warning: Most composts not labelled “peat free” will contain peat.

Members can buy peat-free compost on site at the Trading Hut.