At Woods for the Trees we encourage schools, school age pupils and teachers to grow trees from scratch. Why? Because all the tree nurseries in Britain are not going to be able to keep pace with the demand for trees to plant in new woods in the next decade; and trees – at least many of them – are easy to propagate. Besides, growing trees from nuts or seeds is fun, and a great chance to learn about nature.
Most schools have either some open ground or unused corners with a little bit of sun. All you need to do is collect some nuts or seeds (or buy them from a reputable seed grower – the seeds themselves are very cheap); a suitable container and growing medium; and the dedication to make sure those baby trees keep getting the water they need to grow. And then the trees will just get on with it. After that, you’ll need to find somewhere to plant them permanently…
What do young people gain from growing trees?
- Knowledge of basic tree reproduction and growth
- Satisfaction of having contributed to the drive to halt climate change
- Enjoyment of nurturing and looking after a plant over more than a year
- Learning to improvise and think how to get the materials you need
- Getting out and about in nature, collecting seeds and identifying trees
Which trees to try and grow
Some tree seeds, especially those with the larger nuts, are really easy to grow from seed. Some are more tricky but could be attempted alongside the easy ones. Other trees can be grown from simple cuttings.
What to do and when
There are more detailed instructions below – here’s a summary
|Early Autumn||Collect ripe nuts from oaks, beech, hazel, chestnuts, conkers (easy)|
Take cuttings from willows (easy)
Collect droops off birch trees and shake onto paper – there’ll be hundreds in each droop (easy: see gallery)
Collect berries from rowans, hollies, hawthorns and cherries (easy)
Collect cones from Scots pines and alders (easy)
Plant out tree seedlings from previous year
|Mid-late Autumn||Pot nuts (easy) and put outside in sheltered spot|
Take seeds from berries (fairly easy); bag with moist sharp sand (easy)
Shake seeds from cones (easy) and do the same; also for birch seeds
Pot willow cuttings (easy)
|Winter||Learn to tell trees by their winter buds (tricky, but easier with practice)|
|After Christmas||Put seeds bagged in sharp sand into a fridge for 6 weeks; keep moist but not wet; put Scots pine seeds in fridge.|
|Spring||As soon as it gets drier, put pots in watering trays and keep topping up with water. Check to see what’s shooting and learn to tell between weeds and tree shoots, which are much sturdier.|
Check seeds in bags regularly: pot germinated seeds (those with white or green shoots) into soil-based compost; water them.
|Summer||Keep weeding and watering.|
Find out where you can plant your trees out in autumn.
What you need
A tree and seed identification guide. A good, simple, inexpensive introduction is: https://treecouncil.org.uk/product/the-good-seed-guide
Lots of pots – the larger yoghurt pots will do; or discarded or recycled plant pots from home or a garden centre. A pot of 6-7″ (15-18cm) diameter will do nicely. Make sure they are washed thoroughly before you use them, to help stop spreading plant diseases and mould.
Secateurs (for willow cuttings)
Soil-based compost or garden soil. If you see a mole hill in your garden or in a park, ask if you can have some of the soil – it makes a really good planting medium. Don’t use grow-bag type compost – it’s too rich for most trees and doesn’t hold together well – trees need something a little firmer. You might be able to get a local garden centre to help. Some take part in a scheme in which ordinary customers can buy an extra bag of compost to be donated to a local school.
Lolly stick labels – so you know what you’ve planted and who has planted it – and a permanent marker to write with.
Watering trays. Most young trees die because they don’t get enough water. Young trees don’t need watering in winter, when they should just be left in their pots; but in spring and summer you need your pots to stand in trays and be well watered. You could improvise watering trays from cut down packaging or try to get them donated to you using a garden centre help to buy scheme. Or you could make a rectangular barrier in bricks or logs and line it with plastic sheeting. These are good opportunities to teach improvisation.
Space: you need to keep your seedlings safe and out of the way of browsing animals like rabbits, sheep or deer, if you’re lucky enough to have them roaming your school grounds, and from accidental knocks in the playground.
Autumn is the time for collecting and sowing seeds. Ripe nuts are dull green (acorns) or brown and can be collected from the ground as they fall, although the first nuts shed by a tree are often not the best specimens. Collect them in a paper or cloth bag and label them if you are not confident about telling them apart. It’s worth keeping a seed collecting diary so that you can look back and see which nuts and seeds from which trees have been the most successful. Winged seeds can be picked straight from the tree as soon as they are brown. Berries and other fleshy fruits are ripe when they are at their richest colour, sometimes deep into autumn. Collect cones from the tree or ground when they have turned brown, late on in autumn. Keep them dry in a paper bag until the seeds have dropped out of the cone.
The Tree Council maintains a very useful website that organises, and offers advice on, seed gathering: https://www.treecouncil.org.uk/Take-Part/Seed-Gathering-Season
Growing trees from seed – mimicking nature
The larger fleshy nuts: acorns (from oak trees), hazelnuts, chestnuts, beechnuts and conkers (although the horse chestnut is not a native) are the easiest to propagate, because they carry ample reserves of the energy that a new seedling needs to establish itself. Drop the nuts into a bowl or bucket of water and fish out and discard those that float. Bury the good nuts in pots or directly in the ground, about an inch and a half below the surface and let nature do the rest. We reckon on about a 70% success rate: so if you want 70 trees, plant 100 acorns. Pick the best and freshest nuts and don’t leave them around the house in a paper bag to get dry – just go right ahead and plant them as soon as you can after collecting, two or three to a pot, about 5cm deep (this is the depth that birds and animals bury them for safekeeping; and it’s perfect for germination).
With beech nuts, many of the shiny brown seed casings do not contain an active kernel, but with practice you’ll find you can tell full from empty by gently squeezing them. The plumper ones have nuts in. If you don’t have a nut allergy, try eating them – they’re delicious.
The seeds of alder and Scots pine cones can be sown directly into moist compost in pots, two or three at a time. If you find cones, you can tap the seeds out onto a sheet of paper (see last, new image of the seeds). Keep the pots in a cool, shady spot and see what emerges in spring. Scots pine cones grow one year, then open in spring the following year. By the time summer comes along they’ve usually opened and the seeds have dispersed. But you can also buy packets of Scots pine seeds from tree nursery seed specialists. If you get these in late winter or early spring, you can soak the seeds overnight; drain them: put them in a plastic bag with a couple of holes in, and place the bag in a fridge. Four to six weeks later you should find that most of the seeds have germinated, or sprouted. You can carefully plant them in soil-based compost, two to a pot. They will grow just a few inches in the first year; then accelerate. Mature Scots pines can grow to well over 100ft in height. You could try a few different methods to get some of the trickier seeds going, and compare the results. We’d love to hea how you get on.
There are lots of species of willow. Almost all will ‘strike’ – that is, if you cut a stick of willow from a branch that grew last year (this year’s stem will be green; cut a stick from a little further back on the branch with a pair of sharp secateurs) and stick it in a pot in soil-based compost, there’s a good chance it’ll grow. Obviously, you need permission from the tree’s owner to cut it; but this way you can propagate loads of willows for almost nothing. They like plenty of water and grow best near moist, damp or boggy ground.
Other seeds – the fleshy fruits and winged seeds – need special treatment. They are well worth trying for more ambitious classes; refer to the relevant section in The Little Book of Planting Trees.
Young trees need sun and water – plenty of both. You need to remove invasive weeds that will start to grow in the pot alongside the trees, competing for nutrients. With practice, it’s easy to tell the difference: once you’ve spotted a tree seedling, everything else is a weed! Other than that, they pretty much look after themselves. If you find you have two or more seedlings growing in a pot, re-pot them individually, otherwise their roots will intertwine and they get stuck together.
Watching trees grow is fascinating. If you can, set up a time-lapse camera and watch them work as they send up new shoots vertically and put out leaves to either side. These are great learning opportunities. How many leaves? Do all the trees do the same thing; or are their big differences in each species? Can you learn to identify trees from their leaves in summer and their buds in winter?
Planting the seedlings
Hopefully, your school will be able to make links with a landowner or authority or a parent with a small plot of land, keen to plant your trees out when they are a year old – two years at most. If not, get in touch with Woods for the Trees and we’ll do our best to find a home for them. Your local authority or wildlife trust are good places to start. Even better if there is a small patch of land in the school grounds. Some trees can successfully live in large tubs – rowans and hazels, for example; so you might like to keep some of your trees to brighten up your school’s grounds. Make sure your trees are weed-free when they get planted in their final home.
Here are some images to help you identify seeds and young trees. We would really like to hear how your school’s Nuts for the Trees project goes.