The short version: Stand the punnet in bright shade and water it from below as the mix starts to dry: ten minutes in a tray, then drain, never left sitting in water. After a week, give a weak liquid feed. If planting is more than a fortnight away, pot each seedling on. Harden it off and plant out in the evening.
Day to day
- Light: bright shade, such as the south side of the house or under a tree. A punnet in full sun can dry out within hours on a hot day and cook its roots; a punnet in deep shade stretches and goes pale.
- Water: a punnet holds very little mix, so check it every morning and again on hot afternoons. Bottom watering, ten minutes in a shallow tray or until the surface darkens, then out to drain, wets the root ball without flattening the seedlings; a mix that has dried hard sheds water and needs longer. Lift it before and after; a light punnet is a dry one.
- Not too much: a punnet left sitting in a saucer of water has no air left in the mix and the roots rot. Drain it after every soak.
- Food: seed raising mix carries little fertiliser. After about a week, add a liquid fertiliser or a seaweed and fish mix to the tray water weekly, at the seedling rate on the label or half strength if it gives none. A strong dose burns small roots.
- Weather: bring it under cover for storms, hail and hot wind, and keep it off the ground, where snails and slugs are less likely to reach it.
If it will be longer than two weeks
Roots circle, lower leaves yellow, and a plant held too long rarely catches up fully. If planting is more than a fortnight off, or roots show at the drainage holes, pot each seedling on into a 7 to 10 cm pot of potting mix, water it in, and treat it as above, skipping the weekly feed if the bag says the mix carries fertiliser. That usually buys two or three weeks and a sturdier plant.
Planting out
- Over the last few days, give it a few more hours of morning sun each day, so full sun is not a shock.
- Water the punnet an hour before.
- Plant in the evening, or on a cloudy day, so the seedling settles before it faces the sun.
- Push each seedling up from below rather than pulling it by the stem, set it at the depth it grew, firm it gently, and water it in.
- Shade it for the first couple of days in hot weather, and keep watering until new growth shows.
A punnet on the bench is a promise, and a shady spot and a tray of water keep it.
Related reading
Raise the next punnet yourself from the vegetable seeds collection.