When to start grafting – I think I could write a book on this.
It depends as to whether you are grafting onto
1 – A new rootstock that is bare rooted or potted. This is called bench grafting. That is you do it on a bench, hopefully in the dry and warmth.
1.1 – If it is an apple, you can graft any time from January to just before bud break (March) as long as its kept above 5 deg C and not frosted. If you can keep in a greenhouse or conservatory at say 10 deg C that would be ideal, but no frost.
1.2 – If it’s any other fruit, you must really wait until just before bud break (March), that is when the day and night temperatures have warmed up a bit.
2 – Or onto an existing tree or new rootstock that is already planted in the ground.
2.1 – For any fruit you must really wait until just before bud break (March), that is when the day and night temperatures have warmed up a bit.
Just for info, I try and do all my apples onto bare rooted rootstock in late January and keep in the greenhouse maintained at 10 deg C. Then I do all other fruit onto bare rooted rootstocks in March, and again I keep in the greenhouse at 10 deg C.
All bare rootstocks must be kept damp at all times. I pack all of mine into plastic bins with a little compost, just to retain moisture.
I then wait until something like May and then plant outside.