There is an herbal called comfrey that accelerates healing. If you can find it locally, it will help him heal up faster, so you can work him harder, LOL!

They also use it for a fertilizer 'tea' in organic farming by fermenting. Might be a good plant for you to add, but buy the Russian variant. It must be propogated by root cuttings, so it won't take over like the regular type can. It also makes a good breakfast tea that is good for the GI tract.

I look forward to your post on the greenhouse, always good to see how people build fun things, LOL!

:)>