"Myself and Richard have nerdy horticultural conversations over lunch at GROW HQ occasionally. They are the types of conversations that only veg obsessives could ever really enjoy. This week we’ve been exercised about transplanting tomato plants and specifically whether to plant them out or pot them on at this stage. Sown in February, my plants are now outgrowing the module tray they are in, so I need to make a decision on them, but it seems a little risky to put them out in the polytunnel given the weather we’ve been having. He says he sowed his tomatoes a whole month later than me, so he wouldn’t have the problem that I now face. He calls me a premature germinator...(There's a note in that in the employee handbook now - Ed)
So why not leave them in the module tray? Well, when tomato plants are in a module tray and getting bigger they are competing for light. This can result in you losing the early fruit as the plant wisely decides it won’t have enough light for the first fruit truss.
In theory, potting them up in to their own pots would be a good plan but (a) it will be expensive – all those pots, all that compost and (b) it’s an extra layer of quite considerable work and (c) unless I give them plenty of space the light access problem remains the same. I literally don’t have enough space in the potting shed to provide plenty of space to 70 tomato plants in pots. So I think I’m going to take my chances and plant them out in the tunnel this weekend.
When discussing the potential for cold nights to play havoc with freshly planted tomato plants, I was reminded of a tip I got some years ago from a wise old GIYer - Hugh O’Neill, father of my friend Feargal. Hugh’s tip is simplicity itself - get a sheet of newspaper and pull it down over the cane that’s supporting the tomato plant, making a hole in the centre of the sheet. The paper will then rest gently over the plant, keeping it nice and snug, and can be pulled off again the following morning."