Cropping Plan Overview
Crop selection, bed layout, plant density, and the use of undersowing and mulching within the Farming with Fungi project were determined by a combination of experimental, agronomic, and economic considerations. The cropping plan was designed to support the project’s research objectives—specifically the testing of soil, plant, and fungal interactions using common, widely grown crops—while also ensuring that the site could generate marketable produce to help sustain the project financially. A key outlet for produce has been the National Botanic Garden of Wales café. As a result, the cropping plan reflects a deliberate balance between experimental relevance and practical food production.
Decisions around row number, plant spacing, crop combinations, and crop establishment methods are integral to the experimental rationale of the project. These design choices are intended to influence root density, carbon allocation below ground, microbial activity, and the continuity of arbuscular mycorrhizal hyphal networks across seasons. Undersowing, cover cropping, and mulching are used deliberately to maintain continuous soil cover and minimise disturbance, rather than as secondary fertility inputs.
Across the system, decisions around whether crops are direct-sown or transplanted are made in relation to establishment reliability, early-season growth, and pest pressure, particularly from birds. Several crops are raised in cells and transplanted to ensure uniform establishment and to protect young plants during their most vulnerable stages, especially within a permanent cropping context where re-sowing gaps is undesirable.
Four of the growing blocks operate under a permanent cropping and succession scheme. Under this approach, the same crops are grown in the same beds each year, allowing observation of long-term plant–soil–fungal interactions under repeated cropping pressure.
Within each block, beds are numbered one to seven. Several beds are subdivided longitudinally into sections A and B, allowing paired or complementary crops to be grown within the same bed while maintaining consistent spatial relationships year on year.
What follows is a description of the permanent cropping plan used across these four blocks, with integrated notes on row spacing, plant density, crop establishment, undersowing, mulching, and associated considerations and risks.
Bed 1: Maize (Sweetcorn)
Cropping approach
Sweetcorn is sown in cells in April and transplanted into the beds in May. Plants are established in three parallel rows per bed, with plants spaced at approximately 30 cm within rows. Newly transplanted plants require temporary protection due to significant bird damage pressure on the site. In late June, once the maize is established, the bed is under-sown with a rye, clover, and buckwheat mix. After harvest, the bed is mulched and left undisturbed over winter, ready for replanting the following May.
Considerations and requirements
Sweetcorn is a high-nutrient-demand crop with a strong response to nitrogen availability. The timing of undersowing is critical to avoid early competition while ensuring continuous root presence later in the season.
Risks
Repeated cultivation may increase nutrient drawdown if biomass inputs are insufficient. Bird damage presents a significant early-season risk.
Bed 2: Squash
Cropping approach
Squash is sown in April and transplanted into the beds in May. It is planted as a single row per bed, with plants spaced at approximately 1 metre. Plants are allowed to trail into adjacent beds and permanent comfrey divider beds, increasing spatial complexity and soil shading. The bed is under-sown with clover and phacelia to maintain living ground cover and introduce additional root diversity.
Considerations and requirements
Squash benefits from high organic matter and consistent moisture. Trailing growth reduces soil exposure and evaporation.
Risks
In wet seasons, dense growth may restrict airflow and increase fungal disease pressure.
Bed 3 (A & B): Legumes – Peas and French Beans
Cropping approach
Peas and French beans are raised in cells and transplanted into the beds. This bed is divided into two sections, each consisting of two rows. Permanent poles carry two parallel lines of wire with netting spaced approximately 40 cm apart, allowing harvesting from between the rows and avoiding annual disturbance associated with temporary supports. Bird tape is used during establishment to reduce damage to young plants.
Considerations and requirements
Legumes play a key role in nitrogen fixation. Permanent structures support consistency in root distribution and microbial associations year after year.
Risks
Permanent legume cropping may increase disease pressure if soil biological balance is not maintained. Bird damage is a recurrent establishment risk.
Bed 4A: Potatoes
Cropping approach
This bed is planted annually with potatoes and treated as a standalone permanent cropping bed. Following harvest, the bed is sown with a winter cover crop of rye and vetch.
Considerations and requirements
Cover cropping is essential to stabilise soil structure and restore biological activity after disturbance caused by harvest.
Risks
Permanent potato cropping increases the risk of soil-borne disease and structural degradation if cover crops are poorly established.
Bed 4B: Onions and Parsnips
Cropping approach
Onions are sown from saved seed in January and transplanted into the beds in March. Parsnips are grown from saved seed and direct-sown in March. Onions are planted along the centre of the bed, with parsnips planted on either side to facilitate harvesting. Once onions are lifted, a cover crop mix of rye, vetch, and field beans is sown while parsnips remain in the ground.
Considerations and requirements
The staggered harvest allows partial cover cropping while maintaining living roots for much of the year.
Risks
Repeated cropping may increase disease pressure and nutrient imbalance over time.
Bed 5 (A & B): Spinach, Beetroot, Celery and Celeriac
Cropping approach
Spinach is direct-sown in early March and harvested towards the end of May. Following spinach harvest, the same bed is sown with beetroot. Celery and celeriac are raised in cells and transplanted into the bed. Due to the late harvest of beetroot, celery, and celeriac, this bed is not under-sown with a cover crop. Instead, it receives a final application of fresh grass mulch later in the season.
Considerations and requirements
Mulching maintains soil cover and moisture where establishment of winter cover crops is impractical.
Risks
Late harvesting limits opportunities for living cover establishment.
Bed 6: Leeks and Carrots
Cropping approach
Leeks are grown on in nursery beds within a polytunnel and transplanted into the field in April. Carrots are direct-sown into the beds. Both crops occupy the bed for an extended period, and no cover crop is sown.
Considerations and requirements
Soil protection relies on careful timing of mulching and minimal disturbance during harvest.
Risks
Extended bare periods post-harvest may require additional surface mulching.
Bed 7 (A & B): Brassicas – Red Cabbage and Summer Cabbage
Cropping approach
Brassicas are raised in trays or seed bed, potted on into larger nursery trays, and transplanted into the beds in April to ensure strong early establishment. The bed is divided into two sections planted with red cabbage and summer cabbage.
Considerations and requirements
Brassicas are nutrient-demanding crops with high sulfur requirements and are a useful test group for assessing biological adaptation under permanent cropping.
Risks
Repeated brassica cropping increases the risk of clubroot and other soil-borne diseases.
Polytunnel Cropping Plan: Tomatoes and Cucumbers
Two identical polytunnels, each measuring 12 m × 4 m, form a core component of the cropping system. While both tunnels are used for summer fruiting crops, they also incorporate propagation infrastructure that reduces the total available bed length.
Within each polytunnel, space is allocated for propagation benches and propagation beds, primarily for raising leeks. This reduces the available cropping length to approximately 10 metres of productive tomato and cucumber beds per tunnel.
Tomatoes
Tomatoes are grown in four rows per tunnel, with plants spaced at approximately 50 cm within rows. This layout allows for approximately 80 tomato plants per tunnel. Plants are vertically trained to maximise light interception and airflow. Tomatoes are inoculated with arbuscular mycorrhizal fungi at the propagation stage, following the same principles applied across the outdoor cropping system.
Cucumbers
Cucumbers are grown in two rows per tunnel, with plants spaced at approximately 1 metre. Plants are trained up the sides of the polytunnel structure, allowing efficient use of vertical space and reducing competition with tomatoes. This arrangement allows for approximately 20 cucumber plants per tunnel.
Experimental context
Both polytunnels follow identical cropping, spacing, and inoculation regimes. The sole difference is that one tunnel receives exhaust air channelled from the adjacent mushroom grow rooms, resulting in elevated carbon dioxide concentrations. Environmental monitors are used to track CO₂ levels in both tunnels to assess whether elevated CO₂ influences crop growth, yield, or phenology.
Seasonally, the effect of elevated CO₂ is expected to be more pronounced earlier in the growing season, when ventilation is limited to doors and end windows. During peak summer, increased ventilation may reduce measurable differences between tunnels. This comparison forms a discrete but integrated experiment within the broader Farming with Fungi project.
Rotation Block Cropping Plan
In addition to the permanent succession blocks, one block is managed under a seven-bed rotational system to provide a comparative baseline. Where possible, spatial layout and establishment methods mirror those used in the permanent blocks, but the rotational block differs in crop choice, infrastructure use, and the role of green manures.
Sweetcorn
Sweetcorn is managed identically to the permanent blocks, with three rows per bed and plants spaced at approximately 30 cm within rows. Undersowing and post-harvest management are the same, allowing direct comparison between systems.
Beetroot (successional sowings)
The beetroot phase consists of two rows positioned toward the outer edges of the bed. Four successional sowings are made over the growing season. In addition to beetroot, short-duration catch crops—predominantly lettuce, alongside other salad crops—are sown opportunistically from May onwards to maintain ground cover and productive use of space.
Carrots and leeks
Carrots and leeks are managed in the same way as in the permanent succession blocks, with direct-sown carrots and transplanted leeks occupying the bed for an extended period.
Potatoes
The potato phase occupies a full bed. Post-harvest, the bed is sown with a winter cover crop, consistent with the approach used in the permanent blocks.
Spring-sown green manure
One phase of the rotation is dedicated to a spring-sown mixed green manure. An optimum mix includes species such as oats, vetch, phacelia, and clover, selected to provide rapid ground cover, nitrogen fixation, and a diversity of root architectures early in the season.
Legumes (dwarf beans and broad beans)
The legume phase differs from the permanent blocks in that no permanent support infrastructure is used. Dwarf French beans are grown in rows along each side of the bed, while a central row of broad beans is established. Broad beans are supported with a simple line-and-stake system.
Brassicas
The brassica phase mirrors the permanent blocks in structure but substitutes winter cabbage for summer cabbage, alongside red cabbage. Undersowing and post-harvest cover cropping follow the same principles used elsewhere in the system.
Notes on the Permanent Succession System
The permanent cropping approach is intentionally experimental. It tests whether high organic matter inputs, minimal soil disturbance, continuous living roots, and fungal-supported nutrient cycling can offset the disease and fertility challenges typically associated with non-rotational systems. Outcomes from these blocks inform ongoing refinement of cropping design and soil management strategies.