Once you’ve grown your own seedlings, or bought them at the nursery and brought them home, what’s the best way to get them in the ground and growing well?
There are two main parts to this – the state of the transplant, and the state of the place you’re going to plant them into.
The ideal is to plant your young seedlings as soon as they are ready to grow out of their pot – before their growth is checked, but not so soon that they haven’t filled the pot with roots and the rootball falls apart. I have to admit that most of the time I don’t hit the ideal moment – my transplants almost always have to wait until they are begging to be out of their pots, poor things – but even so, most vegetables are fairly forgiving and you’ll still get decent results. Cauliflower and melons are two kinds that deeply resent being transplanted at the wrong time, though, so be warned!
You can check root growth by very gently and carefully turning the plant upside down and turning it out of its pot into your hand. You’re looking for healthy white roots visible on the outside of the rootball, and a rootball that holds together well.
Apart from the stage of growth, transplants grown indoors or in a greenhouse will need “hardening off” before being planted outside. That means, gradually letting them get used to the new conditions before you plant them. Carrying them in and out is a bit of a performance but better than seeing the whole lot keel over in shock if you don’t bother! To harden them off, give them a short time in good shelter to start with (shelter from sun and wind), then over a period of several days to a week, give them more and more time outside, and more exposure to weather. Watch for sunburn on tender indoor-grown leaves!
The place you’re planning to plant should have had the soil prepared previously so that any added amendments have had time to settle in and break down a bit, and the soil has done any settling it’s going to do. It should be nicely damp, but not soggy (especially if you have clay soil). It should also be warm enough for the species you’re planning to plant. Broccoli doesn’t mind being transplanted into cool soil, but peppers and tomatoes won’t like it at all, and basil will pout for days or even just die!
New transplants benefit from protection from the sun for the first few days. Planting suring a spell of rainy or cloudy weather is great if you can get it, but you can also plant in the evening, and/or use shade cloth or shading structures for protection. Gradually expose the young plants to more and more sun until they settle in and get used to the new conditions.
The physical act of planting is pretty straightforward. Make a big enough hole to take the whole rootball, pop plant out of pot, put in hole, “puddle in” with water if you like, firm soil round roots, next. Some fine points:
- Most plants like to be transplanted with the soil level at the same point on their stem as when they were growing in their pots. Exceptions are tomatoes and peppers, which will grow roots along any stem you bury (don’t bury leaves! pinch them off first), and broccoli and lettuce, which don’t mind having any leggy stem up to the first set of leaves buried. Leggy tomato and pepper seedlings can be much improved by doing this.
- Don’t leave the roots exposed to air for any longer than you have to. Make the holes first, then pop each seedling out of its pot and straight into the hole.
- Don’t firm the soil too hard, especially if you puddled in with water. Some air needs to be left in the soil, you’re just making it firm enough to provide good support for the plant.
- It can help to create a watering basin around each plant. Plant a little deeper than the surrounding general soil level, then scrape the extra soil into a ridge around the plant so it sits in a shallow bowl.
- If you didn’t add fertiliser or compost to the whole bed, most plants appreciate some compost or enriched soil mixed into the bottom of the planting hole.
- If you’ll need support stakes or structures, make sure you install them before the plants get big enough to need them, and before you’ll damage new roots by adding them.
- Some plants benefit from being “pinched out” (the top one or two sets of leaves removed) at planting time. This removes some of the foliage and makes it easier for the disturbed roots to support the plant’s water needs, and also makes it grow bushier. Basil plants are a good example of this.
- Pest protection may be necessary, from collars to Reemay cloth to chicken wire. Take account of the pests that you have to deal with in your garden, and take preventative steps – it’s much better than trying to kill the pests later, after they’ve damaged your plants!
Keep a close eye on your seedlings after planting, to make sure they have enough water, and protection from sun, wind or pests.
