Plug Seeder Use

A plug seeder helps you fill transplant trays with seed quickly and evenly. It is a small tool, but it can speed up spring work on a market farm.

Key points

Plug seeders speed up tray filling and give even placement.
Match plate or needle to the seed.
Label every tray and clean between varieties.
Use dry seed and gentle watering.

What is a plug seeder?

A plug seeder places seed into the cells of a transplant tray. Some are hand tools with a plate of holes. Others use vacuum or a roller. The result is one seed, or a small number, per cell.

They are used by market gardeners, nurseries and small farms who start vegetable and flower transplants indoors or in a greenhouse before moving them to the field.

A farm that sells vegetable transplants at a spring market may fill many trays in a few days, so speed and accuracy matter. A backyard gardener filling two trays may do fine with a hand tool.

How do you choose a plug seeder?

Think about the crops, the tray size you use and how many trays you fill. A hand seeder suits a few trays a week. Higher volume may call for a vacuum unit. Ask whether plates or needles are available for the seed sizes you grow.

Ask about cleaning, parts and support. A small tool that is hard to clean costs more time than it saves.

Compare how each tool handles the smallest seed you grow, since tiny seed is where most hand tools struggle. Try before you buy if you can. A neighboring grower or a farm supply store may let you test a tool on your own seed. Watch how it handles your smallest seed, since tiny seed is where most hand tools struggle.

Tray cell count and size
Seed size range
Volume you need
Parts and cleaning

How do you set up before seeding?

Fill trays with moist seed starting mix to the level your supplier suggests. Do not compact the mix hard. Label the tray before you start so you never lose track of variety and date.

Keep seed packets nearby and clean the seeder between varieties. Mixing seed lots is a common source of trouble.

Work in a clean, well-lit spot and keep the mix evenly damp. Dry mix repels water, and soggy mix can rot seed. Aim for a damp, crumbly feel. Keep trays level on the bench while you fill them, and tap them gently to settle the mix. Uneven fill leads to uneven seed depth, which leads to uneven germination.

How deep should you seed?

Depth depends on the seed. Check the packet and local extension guidance. Use the seeder to place seed, then cover lightly with mix or the material the seed grower suggests. Some seed needs light to germinate, so avoid burying it.

After covering, water gently so seed stays in place. A heavy stream can wash seed out of cells.

Keep notes on sowing date and variety, so you can compare how each batch performs and adjust next year.

What are common problems?

Doubles, empty cells and seed stuck to the tool are the main issues. Static, damp seed and chipped seed can all cause trouble. Check the plate or needle for dirt, and use dry seed.

Keep an eye on germination. Poor results may come from old seed, cold or overly wet mix, or tray conditions, not only the tool.

If you see a problem in one cell or a whole tray, stop and check the tool before filling more trays. One minute of checking can save a whole batch.

Empty cells: check dirt or wrong plate
Doubles: seed too small for plate
Washout: water too hard
Poor germination: seed age, temperature, moisture

How do you care for the seeder?

Brush it clean after each use and wipe it dry. Store it in a clean, dry spot. Replace worn plates or needles per the manual and keep spares for crops you grow most.

If it has a vacuum pump, follow the maker's instructions and keep the cord and plug in good condition. Keep electrical tools away from wet floors.

Sanitize trays and tools between crops to reduce the spread of seedling disease. Your extension office can recommend suitable cleaning practices.

When does it make sense to buy transplants instead?

Seeding takes space, light, heat and time. If you grow only a few flats, buying transplants from a nursery may fit better. If you plant many rows and want specific varieties, starting your own saves money over time and gives you choices.

Ask your extension office about local planting dates, and match your seed starting schedule to them.

Hardening off seedlings before transplanting is a separate step, and your extension office can explain how to do it for your crops.

When to get help: For greenhouse electrical work or heating and lighting issues, call a qualified electrician. For planting dates and variety advice, ask your county extension office.

Sources and further reading

Organization homepages are linked so you can search them for current guidance on this topic.

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