Can you grow lettuce on a bog?

Our Rindle wetter farming trial has just been planted up with this years crop of celery and lettuce. But how do you grow crops on a peat bog, and why would you even try?

Large amounts of the UK’s lowland peatlands have been drained and converted to agricultural use, providing many of our salads, vegetables and cereals. However, this combination of drainage and intensive farming techniques has serious environmental consequences through the release of the carbon previously stored in the peat into the atmosphere when it is exposed to oxygen. Wetter farming, or paludiculture, is the practice of farming with a higher water table to reduce carbon emissions, whilst ensuring that the land remains productive and profitable for our farmers.

Read our blog: What is wetter farming?

At our Rindle wetter farming trial we are investigating how crops including celery, blueberries and now lettuce can be grown on an area of re-wetted agricultural peat.

4 workers planting small green lettuce plants behind a red tractor — Planting lettuce at the Rindle wetter farming trial - Mike Longden

The Rindle wetter farming trial

Now in it’s third year, we are conducting a wetter farming trial on an area of formerly drained peatland in Greater Manchester. The land was sold to Lancashire Wildlife Trust after the farmer was finding it increasingly difficult to get a reliable and profitable crop from the field which was increasingly waterlogged.

By installing water retaining bunds and removing existing field drains we are able to stop water from draining off the field allowing the peat to re-wet. The water table is carefully managed across the site at either 50cm or 30cm below the surface, or at ground level.

What are you growing?

After the very wet start to 2024 sowing has been delayed but after dropping the water levels across the field to 50cm below the surface we have now been able to sow this year’s crop of celery and lettuce. This is the third annual celery crop to be trialled, but the first time that lettuce has been grown. There is also a crop of blueberries which were planted in 2022 and are expected to be harvested in 2025. Each crop is being grown with water levels at both 50cm and 30cm below the surface.

Small celery plugs planted in rows — Celery plugs at the Rindle wetter farming trial - credit Lancashire Wildlife Trust

This year we are aiming to mimic the farming techniques of salad growers on drained peat to give us a direct comparison with the wetter farming trail and a business as usual crop.

Greenhouse gas emissions

We are working with Liverpool John Moores University to take CO₂ and other greenhouse gas emission levels from across the wetter farming trial and also on a local business as usual farm. Readings are taken monthly and also whenever any interventions take place, such as ploughing, sowing, any fertiliser application, and harvesting. By understanding how and when greenhouse gas emissions are at their lowest we can then determine the ‘sweet spot’ between achieving the lowest emissions and the most profitable crop.

Bushy green celery plants — Celery plant at the Rindle wetter farming trial - credit Jenny Bennion, Lancashire Wildlife Trust

When will we be eating boggy salads?

The previous two celery crops have not made it to harvest. The first year the celery grew well and we had a buyer lined up, but two weeks before harvest the celery yellowed off. This was due to the celery having used up the remnant fertiliser that was in the ground from its previous life as a potato field, and it running out of these additional nutrients. The second year the celery crop was outcompeted by weeds. This year the celery will be farmed as closely as possible to the conventional techniques, applying organic nutrients where necessary. However as celery is naturally a bog plant it should enjoy the wetter conditions.

This is the first time that we have trialled a lettuce crop, but due to it’s shallow root system it is hypothesized that the raised water table may have little effect on the crop. However we are only expecting to grow one crop this year, whereas the business as usual farm would grow three over the summer season.

We are also undertaking a number of other wetter farming trails including growing sphagnum moss at the Winmarleigh carbon farm and bulrushes.

Find out more about our wetter farming trials