If you’ve ordered upright tomatoes (all our varieties except Tiny Tim are upright varieties) then it is a good idea to plant them deep. This’ll help them to build a good root structure which in turn will give you healthier, stronger plants.
If you look at your tomato plant before you pop it in the ground, at the base of the stem you will see the stem is slightly darker with lots of little hairs, and the odd bump here and there. All these things are its root system, which will come to life once in contact with the soil. So, by planting your tomatoes a bit deeper, you are enabling the plant to produce more roots. And more roots mean more water and nutrients.
So, how deep to plant? Well, if you strip off any lower leaves at the base of the plant, leaving the top-most leaves intact, you can really plant it quite deep, leaving just the top leaves exposed. But any extra depth you give them will help, even if it’s just an inch or two.