The growing system
Strawberries are planted into peat bags either in January to give a crop in May or in June/July to give a small crop in August/September/October followed by a larger crop in May.
Advantages
- Growing in peat bags removes the risk of soil borne diseases, for example red core, and allows more effective control of watering and feeding.
- The bags are supported at shoulder level so the ripening fruit hangs down allowing easier, quicker picking and free air flow around the berries so reducing botrytis.
- Apart from plant establishment, watering and feeding is through drip nozzles into the bag. The foliage and berries therefore remain dry and the quality of the fruit produced is high.
Disadvantages
- High cost of set-up associated with the system.
- More attention must be paid to nutrition and good crop management.
Peat Bags
The peat in the grow bag should have an open, free draining texture. It is important that the compost does not "slump" as this will lead to a lack of aeration or waterlogging at the roots.
The formulation, the size of the bags and price can vary quite significantly between different supplies.
Water Quality
Water which is very hard ie has a high alkalinity can cause a rise in substrate pH.
The alkalinity is made up of the carbonate and bicarbonate content and water should be tested to determine the levels of these. If the water is very hard then acid should be added to reduce the alkalinity.
| Alkalinity ppm | Water category | Need to add acid |
|---|---|---|
| < 125 | Soft | No |
| 125-200 | Hard | Worth considering |
| 200-300 | Very hard | Yes |
| >300 | Extremely Hard | Yes |
Where the calcium levels are less than 120 ppm, extra Ca in the form of calcium nitrate will be required.
Support
The bags need to be raised 1.4 m - 1.5 m (4½ - 5 feet) off the floor so some form of support is required. The essentials for such a support system are:-
- that it is strong enough to support the combined weight of the crops and bags;
- that it presents no impediment to the fruiting truss;
- that it allows drainage from the bag.
The support system can be made from box section steel, small diameter steel tubing or metal gutters. These can either be suspended on chains from the roof of the growing house structure, provided the load carrying capacity is sufficiently high, or mounted on steel posts securely fixed into the ground.
A high standard of design and construction is important with such support systems to minimise associated health and safety risks.
