Increase Your Success When Transplanting Seedlings

Transplanting seedlings is one of my favourite tasks in the garden. There are a few simple things to consider to give your young plants the best chance to flourish – you want them to thrive, rather than just survive.

Timing

Think about the time of year. Just because certain seedlings are available at your nursery, don’t assume it’s the right time to plant them out. If you’re not sure, read the label – most tell you the best time of year to plant. You could look in gardening books, research online or ask family or friends who are gardeners (they might even give you some seedlings if they’ve bought too many).

You can plant tender plants before the risk of late frosts has passed, provided you listen closely to weather forecasts and are prepared to cover your ‘babies’ with protection or enclose them in a cloche.

Hardening Off

If you’ve grown your seedlings from seed you probably know to harden them off before planting. But if you’re buying them from a nursery take a look at where they’ve been living. Have they been in a glass-house, under shade or exposed to the weather? If you seedlings have been grown outside exposed to the weather, they won’t need hardening off. But if they’ve been pampered, they’ll need a bit of toughening up to prepare them for the real world.

To harden off your seedlings you need to leave them outdoors for a longer time each day. Protect them under a porch or behind shade-cloth, bringing them indoors at night for the first few days. After a couple of days, you can expose them to the morning sun. At the end of a week, they'll be tough enough to transplant to their permanent plot.

Planting Out

The garden bed they are being planted in should already have been prepared with layers of organic matter, compost and mulch. Water seedlings 10-15 minutes before planting out.Before removing seedlings from their containers, arrange them where they will be planted. When you’re happy with the arrangement, use a trowel to dig a hole about twice the size of the rootball. Doing this prep work reduces the length of time that the roots will be exposed (drying out).

Fill each hole with water. This supplies moisture to the plant’s root zone rather than the surface where it may quickly evaporate. Gently ease the first plant from its container, working from the bottom and sides to loosen it. Don’t try and pull it from the container by its stem – you may damage it. Only handle these young plants by their individual leaves or by the root ball. Keeping the rootball intact will help prevent transplant stress, but gently tease the roots to loosen them.

Place the plant into the ground at about the same level that it was growing in its container. Backfill the hole until it is almost level with the soil. I like to add some organic fertilizer at this stage, to give my ‘babies’ a head start. Just use a small amount – you can add more later. Finish backfilling, pressing the soil lightly around the roots to ensure good soil-to-root contact.

Water them in well, avoiding overhead watering, immediately after transplanting. Water daily for about a week until seedlings are well established. Bring mulch around the plant, leaving about a 10cm (4inch) diameter clear around each plant.

Other things to consider

Avoid transplanting vegetable seedlings when the weather is expected to be excessively hot. If you can, choose a day that is cloudy or transplant late in the afternoon or evening so that your plants can recover through the cool of the night, without sunlight beating down on them. If you can’t do this it’s a good idea to provide some temporary shade, particularly in hot weather.

An initial watering with an organic seaweed fertilizer will provide a wide range of nutrients and help reduce stress on your young seedlings.

Get all your equipment ready before you start – hand trowel, gardening gloves, kneeling pad, your water bottle and hat.

Tomatoes are an exception to the rule as far as planting depth goes. You can plant them right down to the first set of true leaves. They will grow new roots right up to the soil level, making them more sturdy.

Seedlings from the Cucumber family (cucumbers, squash, pumpkins, melons) do better planted in mounds. This allows for better drainage and warms their soil to give them a better start.