I have read that soil in a greenhouse bed needs to be replaced after 3 – 5 years to avoid the build-up of pests etc. Is this still an issue if you apply the annual dressing of 2 – 3 inches of compost/ manure?
I have created a raised bed in my greenhouse so that an annual application of this depth is easy to apply but I’m concerned that time spent improving the soil will be wasted every 3 – 5 years by starting from scratch. Maybe you can work round this issue by some sort of crop rotation, although I’d ideally like to grow tomatoes there every year?
This is a tricky one because soil pests do build up, but I find that tomatoes every second year in my tunnels works fine, with two inches of manure on top and salad throughout winter.
To a point, soil pests hellp fruit to ripen by making plants less exuberant! But only to a point. My trials of grafted plants have seen them grow abundantly but make no more fruit than ungrafted ones of the same variety.
I would go for it, toms every year, and as much compost/manure on top of the bed as you can fit.