Sow Your Vegetable Seeds: Trays, Cells, Pots Explained

Posted on 18. Feb, 2012 by Tracey in Sow Seeds

The choice of pots, trays and cells on the market is huge and sometimes confusing for anyone to know what to buy to start sowing vegetables seeds. Here I explain the advantages and disadvantages between each of the containers and offer some alternatives and shortcuts for those who wish to get sowing quickly.

Seed Tray

Seed Trays

Description: Seed Trays are plastic rectangular trays with small drainage holes in the bottom.
Used With: They can be used with watering trays to uptake water from the bottom of the tray instead of watering the top.

Advantages: Very cheap, re-usable, easy and quick to sow seeds, if used with a watering tray, the seed tray is easy to water. Lots of seeds can be sown in a seed tray.
Disadvantages: Thinning out the seedlings and transplanting them is fiddly especially if seeds are sown close together. Transplanting takes a fair amount of time.

Watering Tray

Watering Trays

Description: Watering trays are usually black or green rectangular trays with no drainage holes. They hold water so that the seed trays can use capillary action and water themselves from underneath so that the roots can uptake the water efficiently instead of being watered from the top of the soil.

Advantages: Available in different sizes, long lasting, capillary water uptake is effective for the roots and plants.
Disadvantages: Try not to overwater or underwater the water tray otherwise seedlings could drown or become stressed.

Multi-Cell Tray

Multi-Cell or Module Trays

Description: Module trays are usually made from green, black or brown plastic, polystyrene, cardboard or coir with individual plug cells moulded into them. The cells are all joined together. The individual cells vary in size, depth and numbers from 4 to several hundred.

Advantages: Seeds that are sown direct into cells can be easily transplanted with hardly any disturbance to the seedling roots. The individual cells can be pushed from the bottom to quickly and easily turn out each seedling or ‘plug plant’ for potting into a larger pot or into the ground. Other advantages are they can be re-used, used in watering trays and very flexible.

Disadvantages: If the module trays are manufactured from thin plastic and with exposure to sunlight, they may not last for many years. The individual cells can only hold one or a few seeds to each cell.

Plug Trays

Description: Plug trays are usually black plastic with tiny individual plug cells, these come in 84 or 180 where the actually plug size is between 2 cm and 3.5cm square.
Advantages: Seeds can be sown quickly and then can easily be transplanted into multi-cell trays or pots.
Disadvantages: The plug cells are very small so sowing and planting on can be fiddly.

Small Black Pot

Plastic Pots

Plastic pots come in all shapes and sizes, the most common sizes for sowing and potting on plants are as follows:

Small Plastic Pots
Description: Usually lightweight plastic either black or brown, squares or round.
Size: 9cm (3.5 Inches) Wide and 6.8 to 9cm deep.
Uses: Sowing seeds, potting on cuttings or transplanted seedlings.

Medium Plastic Pots
Description: Usually strong sturdy plastic either black or brown, squares or round.
Size: 10.16 to 25.40 cm (4 -10 Inches) Wide and 9 – 26cm deep.
Uses: Potting on cuttings, plants or transplanted seedlings from smaller pots.

Advantages: Plastic pots can be washed and re-used year after year and they are very cheap.
Disadvantages: Plastic pots can be stackable but need storage space.

Shuttle Tray with Pots

Biodegradable Pots and Pellets

Peat Free Jiffy Pellets

These are sold as flat pellets which look like an ice hockey puck. They are a container and media in one and by adding water they expand and are made from peat free coir (coconut husk). Seeds can be placed in the pellet coir medium and then the whole pellet can be planted out into the ground or potted on.

Coir Pots

Advantages: Biodegradable, peat free, environmentally friendly way of sowing seeds. Very convenient to plant in, no need for pots or pot trays. There is no root disturbance.
Disadvantages: The pellet has the nutrients in its container and doesn’t receive fresh nutrients until it is planted/potted on.

Coir Pots

Also available are Jiffy pots and Coir pots where the whole pot can be planted out into the ground and the pot biodegrades over time into the soil. The plant roots can grow through the pot into the soil. This is quite an easy way of starting to grow your own vegetables without the need of any storage for pots.

Root Trainers

Specialist Growing Cells

Root Trainers

Root-Trainers are plastic vacuum pack strips and each strip contains 5 deep cells. They fold out and clip together to make deep long channels to sow seeds in like peas, beans, onions.

Advantages: They minimise root disturbance, they come in two depth levels to help establish seeds. Long lasting plastic containers.
Disadvantages: They tend to be quite expensive however you can sometimes find second hand root-trainers on Ebay. They are a worthwhile purchase and do last a long time.

Guttering Trays

This is a short plastic length of guttering usually with removable end pieces. Vegetables like peas radish, beetroot actually almost any vegetable that requires shallow soil can be sown in this way. Then when the end pieces are removed the compost and vegetable plants can be slid out into the vegetable plot with minimal root disturbance.

Advantages: If you have a particular pest problem, seeds can be started in the guttering and planted out as stronger plants to be able to cope with the problems.
Disadvantages: Cost, these are quite expensive for small lengths. However there is no problem using normal house guttering if you can find lengths on Ebay or freecycle.

Sowing Shortcuts Summary

If you are still not sure what option to go for, these shortcuts may help make things easy for you, to start sowing your own seeds:

If you don’t mind fiddly transplanting, then use Seed Trays.
If you have the room and want quick transplanting, then use Multi-cell trays,
If you are sowing lots of the same seeds but don’t want fiddly transplanting, go for the plug trays, then pot on to larger multi-cell trays.
If you want the green eco friendly option, use the biodegradable pots like Coir or make your own pots.
If you don’t want to fuss about with compost or buying pots, then use the coir pellets in coir pots or trays.
If you are sowing peas or beans, then consider the specialist options of root-trainers and pea guttering trays or just use inner toilet roll or kitchen roll tubes.

Hints on What Pot to Use for Vegetable Types

Bean Seeds

Sowing Tomatoes, Peppers or Chilli’s – Use Seed Trays so you can pick the strongest plants to pot into small pots.
Sowing Runner, French or Climbing Beans – Use Root-trainers, toilet roll inner tubes, kitchen roll tubes, or make your own pots out of newspaper,
Sowing Peas – Use Guttering, jiffy pellets or jiffy pots to minimise root disturbance.
Sowing Onions or Leeks – Use Seed Trays, then transplant to pots or sow in Root Trainers if planting into the ground.
Sowing Beetroot, Spinach, Chard – Sow in seed trays, then transplant to pots.