Planting Out Vegetable Seedlings

Planting Out Vegetable Seedlings

Planting out seedlings - header image

O.K., so you've managed to produce your own seedling plants or have bought in some promising looking specimens. You have hardened them off and are ready to put them out into your garden (or in the case of warm climate crops, to plant them in your greenhouse or polytunnel). You want to make sure they get off to a good start, and hopefully produce abundant supplies of delicious homegrown vegetables.

It's not difficult, especially if you have good plants, but there are a couple of tips which might be helpful.

healthy garden soil

Get your soil right.
Prepare your soil with plenty of garden compost and well rotted manure to give the new seedlings plenty of nutrients. If you read my posts you'll be of sick hearing 'it's all about about the soil', but there's no getting around the fact. If you build a good-quality soil with plenty of organic material you will suddenly find you have the greenest fingers around. That's it, there's no mysterious secret.

If you don't have garden compost I recommend envirogrind soil improver, which is the best and most well-balanced compost we have found in Ireland. Envirogrind contains a high percentage of composted fish waste, which adds a host of beneficial amino acids and nutrients.

Envirogrind can simply be added to the soil surface, which is preferable to digging and disturbing the soil.

Planting depths for different vegetable seedlings.
This is quite a general guide which covers most of the well known garden vegetables. I include the little illustration we send out with all our seedling packs below to show our recommended planting depth.

Vegetable Seedling Planting Depth Guide

Up to the first set of leaves. 
As you can see in the first column, the plants are planted up to the first set of leaves. This is very handy if you have a seedling that is a little leggy, as you can bury a good proportion of the stem in the soil. This is worth remembering as if seedlings in the first group get a bit leggy in the greenhouse, they can be rectified when planting out.

The plants will produce roots from the buried stem which in some cases, tomatoes for example, will improve the root system of the plant. Have a look at the tomato seedling in the picture where you can see the portion of the stem to be planted below my finger and thumb.

Tomato seedling with portion of the stem to be planted

Soil level. 
Plants in the second column have stems which are likely to rot if covered up. Kohl rabi and beetroot are the ones you are likely to get caught out on, as you would expect to plant them deeper. Both of these plants form their bulbous root or stem above ground and shouldn't be covered up. 

Plant the seedlings in this group with the top of the compost in the plug level with the surrounding soil.

Above Soil Level.
Lettuce seedling stems can rot very easily, so it can be helpful to plant the compost plug slightly above the surrounding soil level to keep it away from the moist ground below.

Can we get on with planting them now?
Alright. Rake out and remove large stones or lumps of soil from your intended planting area. Make a hole roughly the size of the seedling plug you wish to plant with a hand trowel or dibber (A dibber is a tool for making planting holes). 

If the soil is very dry, water to achieve a good damp consistency. 

Remove the seedling from the module or plant tray by gently squeezing around the plant to loosen the roots. The seedling should come out easily bit can be helped by pushing a pen up through the base of the module to release it. You can gently tease the roots out at this stage if they have formed a tight mass at the base of the plug.

Teasing roots out of a bean seedling

Place the seedling in the planting hole and firm the soil in around the plant to remove any air pockets. This part is worth noting, as most people press downward around the seedling: which compacts the top of the soil rather than firming in around the plant. 

The motion required is more pushing the soil around the plant like tucking the duvet around yourself on a cold night. Those of you with small children will be very familiar with the action I suspect.

Water your seedlings well after planting. Keep the soil moist and don't let it dry out for the next week or two when the plants are settling in. 

Don't be alarmed if there is very little growth for the first week, as it takes time for the plant to adjust to it's new surroundings. All the energy is going into the root department to build a water and nutrient supply to make sure the plant survives.

Horticultural fleece and seedlings

Protect your plants
The majority of seedlings will be planted in late April - early May when there may still be a risk of frost about. Keep a roll of horticultural fleece handy, it's the best investment you'll ever make. It's relatively cheap but will protect tender plants from a mild frost which would otherwise wipe them out. 

Remember, the new shoots of potato plants which will be starting to come up soon are also frost tender and may need protection.

Fleece is a very light material which will insulate seedlings from temperatures down to -3 or -4 degrees, particularly if you opt for fleece with a higher gsm (or grams per square metre). Simply lay the fleece over the plants you want to protect, and anchor the edges with some large stones. 

The material is so light that it wont damage the growing plants, but is best pulled reasonably tight to stop it flapping in the wind. Fleece allows light and water to penetrate, so can also be left on top of seedlings for a few days if required.

Keep an eye our for slugs and use a slug beer trap if you think you have a problem. A night time trip out to the vegetable garden with a torch can be quite an eye opener and will give you a good idea of slug populations.