Growing note 03 · Start small

A windowsill setup without the gadget pile

Start with one crop and one small tray. The limiting factor is often light and space for seedlings, not a shortage of equipment.

Check the destination before sowing

Decide where the plants will grow to maturity. A windowsill full of seedlings is not useful if you have nowhere suitable to plant them. Read the seed packet for sowing depth, temperature and spacing. Crops differ: some prefer direct sowing and do not suit this method.

A basic kit

• A clean small pot or module tray with drainage holes.
• A waterproof catch tray that protects the sill, without leaving pots submerged.
• Fresh peat-free seed compost or a medium recommended on the packet.
• Labels, a pencil and a small watering can or other gentle watering method.
• A bright position, away from curtains, cold draughts and excessive radiator heat.

Reused containers are fine if clean, stable and safely drained. Keep seeds and gardening materials away from young children and pets. If you cannot give seedlings enough light, buying a few young plants later can be the simpler option.

A tomato example—not a calendar for every seed

For tomatoes destined to grow outdoors, RHS suggests sowing from late March to early April. Germination needs about 18°C. A clear cover can retain moisture until seedlings emerge; remove it promptly at emergence and give as much light as possible.

Keep compost moist, not saturated. Once seedlings have a couple of true leaves, transplant carefully into individual pots, supporting the roots and handling a leaf rather than crushing the stem. Do not assume a tomato’s warmth requirements apply to lettuce or peas.

Read the early warning signs

• Thin, leaning seedlings: light may be inadequate. Move to a brighter safe position; sow fewer or later next time rather than simply adding heat.
• Persistently wet compost: check drainage and reduce watering. A cover is not a reason to keep adding water.
• Crowded roots and leaves: pot on when appropriate; do not keep increasing the number of seedlings beyond your available space.

Outside is a separate step

Harden off tender plants gradually before planting outdoors, and wait until frost risk and temperatures suit the crop. Dates vary across Ireland and the UK. A sunny afternoon does not mean the night is warm enough. Record sowing, emergence and potting dates so you can refine the timing next year.

Sources & limits