Article - The River Blog

It’s Acorn-Growing Season!

Author: Year in Industry Student Placement
Categories: Nature, Tree planting


Native oaks support more insect species than any other tree. They can live for a very long time and provide a range of habitats for plants and animals even after they die.

You can play a vital part in protecting trees of our future. They are a powerful tool to combat climate change by capturing and storing carbon from the atmosphere.

What do I need?

  • Containers to grow the seeds: old milk cartons, yoghurt pots, plastic bottles, buckets and old plant pots (make sure to add drain holes if there aren’t any)
  • Appropriate soil: if you have your own compost then this is the perfect opportunity to put it to use! If not, you can buy compost from your local garden centre, but try to choose a peat-free option (removing peat from peat bogs releases a lot of greenhouse gas)
  • Acorns! Tree seeds like acorns are harvested in the Autumn. Head to a spot that you know has oak trees, and harvest away. Try and stick to native oak species. The two native UK species are pedunculate oak (Quercus robur) and sessile oak (Quercus petraea). Try and collect seed from a number of individual trees as this will help to maintain genetic diversity. Choose old oak trees if you can, as they are well suited to the local climate of your area. Check that your acorns are healthy by dropping them into a bucket of water. Discard any that float.

Plant the acorns into the pots of compost, making sure each one is covered by 2-4cm of compost. Keep the compost damp for the seeds to germinate. Once your trees are about 30 or 40cm tall, after one or two years, they are ready to be planted into their final home. Plant to the same depth as they were previously growing and keep well-watered, fed and weed-free.


Some other seeds to collect and grow in Autumn…

Alder: Pick alder cones before they ripen. Put the cones on a small tray in the warmth so that they open. Harvest the small seeds inside, and store until planting. Early flowering, good for insects. Seeds last for a long time, providing food for birds. This tree loves river banks and wetlands.

Blackthorn: Early flowering, so good for insects. Provides cover and food (berries) for birds. Grows almost anywhere, even in windswept, coastal conditions. Pick the sloes when they are ripe (dark purple). Protect stratifying seeds from mice using wire mesh. Store seeds in a mix of sand and damp leaf-litter for up to 18 months before planting. They will be ready to sow in the first spring following collection.

Seeds from berries and fruits must be extracted before being used to grow plants. Fruits can first be soaked to soften them, without letting them ferment…

Photo credit to Belfast TCV – Conservation Volunteers Northern Ireland. The Autumn Seed Harvest Handbook

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