Hi Charles, I have recently purchased a20ft by 10ft polytunnel for my allotment and will be erecting it in the spring as I am currently clearing the ground it is going to occupy. After watching your you tube video about tomatoes I noticed you grow straight from the ground soil, my question is will I need to change the soil after growing ? as I remember growing in the ground in a greenhouse many years ago and having to change the soil so I grow in 20 or 30 litre pots now in my own homemade compost with healthy results. The spent compost is then used to mulch other beds mixed with compost.