However thinly you sow seeds you will inevitably find that they emerge from the soil too close together. You need to thin the seedlings in order to allow nearby seeds the space, water and nutrients to grow and develop into healthy plants. Do not attempt to thin on only one occasion, you should repeat the operation several times.
Thinning should be carried out as soon as the seedlings are large enough to handle, usually when they have their second set of true leaves. Water the ground prior thinning in order to minimise damage to the roots.
Select which seedling you want to remove, choosing the healthiest and best positioned seedlings. Place your hand around the seedling, holding down the soil with your other hand, and gently lift the seedling. If they are too close to lift without disturbance then you may wish to remove the top growth of unwanted seedlings. After lifting, firm the soil around the seedlings and water gently.
You may wish to move seedlings to their permanent location when they have germinated. They may be seedlings you have grown in pots, trays or in a seed bed. Not all plants are suitable to be transplanted, and sometimes thinning is more appropriate.
Brassicas, beans and peas transplant well, whilst root crops do not and should be avoided. Transplanting seedlings can be very stressful for the plant. In order to successfully transplant seedlings ensure that the risk of frost has passed and water after planting if conditions are dry.
Select a suitable area to transplant your seedlings too and ensure the soil is cultivated to a fine tilth, adding manure where necessary. Water the seedlings and transplant site well the day prior to transplanting. Gently remove your seedlings with a trowel and place the seedlings into the new area at the same depth as the pot or bed from which they were removed. After transplanting, firm the soil and water gently.
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