We use some essential cookies to make this website work.
We’d like to set additional cookies to understand how you use forestresearch.gov.uk, remember your settings and improve our services.
Preparing to search
10-15% @ < 0°C
16 (16-20) weeks warm (c. 15°C) plus
16 (16-20) weeks cold (c. 4°C)
Only partially effective even with the longest pretreatment durations and/or several pretreatment cyclesApproximate date to initiate artificial pre-treatment (for 1 March sowing) 19 July
Orthodox – seeds that can be dried without harm, and once dried can be frozen, stored for years with little deterioration and relatively easily revived.
Figures in brackets indicate that different seedlots often require different pretreatment durations. There are three potential courses of action:
Raising Trees and Shrubs from Seed (PDF-648K)
Forestry Commission Practice Guide 18.
Cookies are files saved on your phone, tablet or computer when you visit a website.
Find out more about cookies on forestresearch.gov.uk
We use 3 types of cookie. You can choose which cookies you're happy for us to use.
These essential cookies do things like remember your progress through a form. They always need to be on.
We use Google Analytics to measure how you use the website so we can improve it based on user needs. Google Analytics sets cookies that store anonymised information about: how you got to the site the pages you visit on forestresearch.gov.uk and how long you spend on each page what you click on while you're visiting the site
Some forestresearch.gov.uk pages may contain content from other sites, like YouTube or Flickr, which may set their own cookies. These sites are sometimes called ‘third party’ services. This tells us how many people are seeing the content and whether it’s useful.