I don't know anything yet about summer grafting. I have figured out that grafting the third week of February to the first week of March significantly cuts energy costs. Don't even think of grafting (in a greenhouse) any earlier if you can avoid it.

I have heard that grafting conifers in summer can be done but I never did again ask the guy I know who does it because at that time he was trying to keep my life simple. Even his success rates drop and he's a 90+% grafter during winter, able to graft something like 5000 grafts and cuttings. He can graft a scion the size of a toothpick, successfully.

Good luck. I use 'Consan 20' every two weeks. It's a combo algaecide/fungicide. I think I would try almost full shade in your case. You need to balance the temp (don't be worried about 80F just be worried when it goes past that)...balancing temp with humidity over 90%. Should be just like winter grafting.

Dax

Thanks!
In the course of the week 90+ F are expected in my region and then I will place them in my basement (60F) during the hottest part of the day.
I'm hoping for a better result than last winter/spring, because last spring a lot bud's broke out but starved after a few weeks. I think this was because of the strong sap-stream, something I'm avoiding this time.
I will keep everyone informed, although the results will only be there next spring.....

Can Picea pungens be grafted onto Picea abies? I would think that pungens would need to be grafted onto pungens seedling understock, correct?
Thanks,
Mike

Hi Mike,

All the Picea's graft successfully onto each other. The same applies for Abies.

Dax

Please keep us posted on your results.
If you moved to basement - would there be need for additional lighting?
I am waiting for cutting of a Broom, that is too high for me to reach, and must rely on an arborist to come on the property and reach with a truck and lift.
When it is cut I will try to graft - ( pinus strobus) so your summer time grafting process will be helpful.

Are you waxing the rubber bands, or do you use the flexible clear grafting tape? Dax discussed in previous posts - so I tried and was fairly sucessful.

Mike

Thanks for your respons, Mike.
I'm not waxing, I just use raffia-tape. After three months after the grafing I'm planning to remove it.
Till now, the grafts are doing fine: all the scions still have the same blue color. During the heat wave I didn't place them in my basement (this was the intention, yes), but just moved them into my house for a couple of days. There was enough light in that place and temperatures stayed around 25C (75F) there, and that's not harmfull, I've read from Dax.

Now the grafts are in a place with shade (almost) all day long. It's just a period between 10 and 11 AM when the sun shines on that place. During that sunny hour I cover them with a sheet, so they don't get the direct sunlight and this method also prevents heating them up.
The first two weeks I didn't ventilate them at all (ofcourse I used a fungicide), in the third week I ventilated half of the days for about half an hour and misted them afterwards. Now, in the fourth week I ventilate each day. Next week I will ventilate every day too, but a bit longer.

After about eight weeks I hope that the unions will be healed. It's mid-october by then, and from then I will place them in a cold greenhouse. It's Picea pungens, so they need freezing temperatures in winter, but I will not place them in harmfull sunshine/cold wind comditions. A long period of frosts is good for them. I think it will harm them when I place the grafts in an above-freezing environment all winter long.