Calling all tree nursery enthusiasts and seed gatherers! Have you been taking advantage of this year’s plentiful supply of acorns? Or, perhaps last year’s acorn drought still has you scratching your heads? If so, read our rundown of acorn collection tips, tricks, and know-how below.
Acorn Collection: Tips
The good news is there are a lot more acorns this year than last. The bad news is they have been dropping earlier than expected. This is likely due to the stress caused by 2022’s hot and dry summer, which has caused oak trees to shed their resource-heavy seeds. So, if you haven’t already done so, be sure to find time over the next few weeks to get outside and gather your acorn harvest for the year.
Officially, seed collection season runs from 23rd September (the start of autumn) to 23rd October. This is the ideal time to collect most native woodland tree seeds in the UK. However, when it comes to acorns, we think it is better to collect them from October to November, when they have had a chance to ripen. This is because ripe acorns, characterised by their brown skin, stand a better chance of germinating and becoming healthy young trees.
Another tip is to try and gather larger acorns, where possible. At Moor Trees, we find that larger acorns are a little more likely to both germinate and become established. The most likely reason for this is that larger acorns have more nutrients in them, giving tap roots and young shoots more food in their early development.
Acorn Collection: Tricks
The best way to tell if an acorn is healthy and likely to germinate is by giving it a visual inspection. Here are some things to look out for:
- Colour: they should be green, brown, or somewhere in between – as mentioned above, we find that browner acorns do a better job of germinating
- Surface: you want acorns that look smooth and shiny
- Signs of damage: check for small cracks or holes – holes may be the result of an insect burrowing beneath the acorn’s surface and should be discarded
- Caps: these should come off easily
Once gathered, acorns should be ready to plant in either growing containers or their natural habitat. They can also be stored for several months, so long as they are kept cool and don’t dry out.
Acorn Collection: Know-How
Did you notice there were hardly any acorns last year in 2021? Things were no different here in Dartmoor. In fact, we only managed to collect a total of 10 acorns in the entire seed collection season! That’s because 2020 was a mast year for oak trees.
Mast years take place roughly every 5-10 years and are characterised by a ‘bumper’ crop of acorns. This bumper crop means oak trees put much of their energy into producing acorns and little into growing. As such, to counteract this behaviour, there is often a scarcity of acorns in the year that follows a mast year as oaks put their energy back into growing, hence the low number of acorns produced in 2021.
What is fascinating about mast years is the incredible synchronisation that happens among oak trees across the UK, and indeed the rest of Europe, that enables the mass production of acorns to take place. Little is known about this phenomenon, although there is some speculation that the answer may lie in weather conditions or the mycorrhizal relationship between fungus and trees.
To discover more acorn collection tips, how to keep your oak seedlings happy and healthy, as well as tips for lots of other types of seed, why not consider purchasing The Tree Grower’s Guide?
