Bolt
A plant is said to bolt when it tries to flower and set seed. This is usually a premature action.
Cells
These are trays divided into several sections, used for sowing seeds.
Cut-and-come-again
This usually refers to varieties of salad leaves where more leaves will grow after the first ones are harvested. Plants can be repeatedly cut or picked.
Drill
This is a depression made in the ground in which seeds can be sown. It will usually be 1–2cm/½–¾in deep and in a straight line marked with sticks and string.
Earthing up
This is the action of piling soil around the stem of a plant. It usually applies to potatoes, but the technique is also used with cucumbers and melons.
Harden off
Plants should be slowly acclimatized to growing in lower temperatures than those in which they have been raised. This process is called ‘hardening off’. It can take several days.
In situ
Seed is sown in situ when it is sown directly into the ground where the plants will remain.
Mist
To ‘mist’ leaves and plants is to damp them with a fine spray of water.
pH
This is a measure of acidity and alkalinity. A neutral soil is pH 7. Above this is alkaline, below it is acid.
Root-trainers
These are special long cells used for raising long-rooted seedlings.