As an alternative to pots and trays it is possible to substitute a system that obviates their use: the idea simply being to plant out or pot on the entire unit. This is achieved by eliminating a pot altogether, either by using a peat compost, compressed into a pellet and contained within a net, that swells up when soaked with water, or by compressing the compost into blocks.
These systems are useful, very effective and reduce the ultimate root disturbance to a minimum, which means the growth of the young plants is not checked when they are transplanted.
The high initial cost of purchasing a soil block mould may deter many gardeners who do not propagate large quantities of cuttings and seedlings. It is best to make hexagonal soil blocks as they do not dry out so readily provided their sides touch each other. To make a soil block successfully it is important to ensure that the compost has the correct level of dampness. To test this, take a handful of moist compost. Squeeze gently but firmly; the compost should tend to crumble. If it falls apart, the material is too dry; if it does not start to crumble, it is too moist.
Fill the mould with the compost, compressing it only until the particles form a block. Place the soil block on a tray and leave it to consolidate for 24 hours before inserting a seed or cutting. As the plant grows the roots hold the block together. Plant out as soon as the roots emerge through the sides of the soil block.
1 Hold the soil block mould with one hand on either side. Push the mould into some damp compost.
2 Release from the mould when full, and stand on a tray. Leave to consolidate for about 24 hours.
3 Insert a seed or cutting and cover with compost. Ensure that the sides of the soil blocks are touching.
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