How To Grow Trees From Seed

Learning to grow trees from seed costs almost nothing and is a lovely, slow project for the whole household. A pot of compost, a handful of acorns or nuts and a bit of patience are all you need. It does take time, and not every seed will come up, but watching a seedling push through in spring is hugely satisfying.

This guide covers choosing and collecting seed, getting it ready to sow, planting it up and caring for the young trees until they are ready for the ground.

Choosing Which Trees To Grow

If you want to grow trees from seed for the first time, large seeds are the easiest place to start. The Woodland Trust suggests beechmast, sweet chestnuts, hazelnuts and acorns, all of which are easy to find in autumn. The RHS also recommends big tree seeds such as oak and sycamore as good choices for children.

Think about space before you start. Many native trees grow very large, so decide early whether a seedling will go in your own garden, be given to a friend or neighbour with room, or join a community planting scheme.

It also helps to know that seed from a named garden variety will not usually produce a copy of its parent. The RHS notes that named cultivars do not come true from seed, while species plants usually do. Wild-type trees are the most reliable choice.

Collecting Seed Responsibly

Collect seed on a dry day as soon as it is ripe, before it falls and scatters. A change of colour from green to brown or black is usually a good sign. For acorns, the RHS suggests collecting from mid-September to December and choosing ones that are green or brown, have no insect holes and whose caps come away easily.

Only gather from your own garden, or from land where you have permission. The Woodland Trust’s foraging guidelines point out that all wild plants are protected under the Wildlife and Countryside Act 1981, and that it is illegal to dig up or remove a plant without the landowner’s permission. Take only what you need and leave plenty behind, because nuts and seeds are important food for wildlife.

Storing Seed Until Sowing

Sowing fresh is best, as many tree seeds become harder to germinate once they have been kept for a while. Some, including oaks and walnuts, must not dry out at all. The RHS advises keeping these in a plastic bag of damp vermiculite, sand, or moist coir and sand in the fridge until you sow.

If your seed comes inside a fleshy fruit, such as a berry, mash the fruit in a fine sieve, rinse away the pulp in cold water and let the seed dry for a few days on kitchen paper.

Breaking Dormancy With A Winter Chill

Many tree seeds will not germinate until they have been through a cold spell, just as they would outdoors over winter. There are two simple ways to give them this:

• Sow in autumn and leave the pots outside. Winter does the work for you, and seedlings appear as the days lengthen in spring.
• Chill them in the fridge. The RHS describes mixing seed with moist but not wet coir or composted bark in a sealed bag and keeping it below 5°C for four to 20 weeks, depending on the species. Shake the bag now and then and sow straight away if any seeds start to sprout.

Be prepared for germination to be slow and uneven. The RHS notes that some tree seeds do not come up until their second spring, so do not give up on a pot too soon.

How To Grow Trees From Seed In Pots

1. Choose a pot with drainage holes. The RHS suggests 15cm pots for acorns.
2. Fill it with compost. Peat-free seed compost works, or the RHS mix of half multi-purpose compost and half coarse grit for better drainage. Leave a small gap at the top.
3. Sow the seeds. The Woodland Trust recommends pushing seeds about 2cm deep, then firming the compost and watering thoroughly. Several acorns can share one pot, spaced around the edge.
4. Place the pot outside in a shady corner. Cover it with wire mesh to stop birds and other animals getting at the seeds.
5. Label it. Write the tree name and date on a label so you know what is coming up months later.

Check the pot every week so the compost does not dry out, but be careful not to overwater. The Woodland Trust’s guide to growing a tree from seed has a simple illustrated version of these steps that works well with children.

Caring For Your Seedlings

Once seedlings appear and are large enough to handle, move each one into its own pot. Pot them on into larger containers as they grow, particularly once roots start to poke out of the drainage holes.

Young trees are easy targets for hungry animals. If rabbits or mice are a problem, the Woodland Trust suggests a simple guard made from a cut-down plastic bottle. Keep pots sheltered in winter to protect them from hard frost, and keep watering during dry spells in summer.

Planting Out

When you grow trees from seed, you do not need to rush planting out. The RHS says oak saplings can stay in pots for two or three years, while the Woodland Trust suggests moving a young tree into the ground once it reaches about 40cm tall. Autumn is a good time to plant, as it gives the roots the winter to settle in before growth starts again.

Choose the final spot carefully, bearing in mind how big the tree will be when mature and keeping it well away from buildings, drains and boundaries where it could cause problems later.

A Simple Plan To Grow Trees From Seed

• Pick up a few acorns, hazelnuts or sweet chestnuts in autumn, with permission.
• Sow them fresh, about 2cm deep, in a pot of free-draining compost.
• Leave the pot outside in a shady spot, covered with wire mesh.
• Keep it just moist and be patient; some seeds take more than one spring.
• Pot on the seedlings and plant out once they are big enough.

Wear gloves when handling compost, and wash hands afterwards, especially if children are helping. For more hands-on projects, have a look at our garden and DIY guides.

There’s plenty more help for UK gardeners over on Beyond The Garden Gates.

Kaan Rassad

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