You will be most satisfied if you train your plants so they will be as off the ground as possible, to avoid rot, pest damage and discoloration. Put stakes at opposite sides of the cylinder and tie cylinder firmly to them. As the vine grows, poke protruding branches back inside, and reach through screen to pick the fruit. Here is some information on the most common problems one might encounter with tomatoes. It is caused by uneven watering practices and a lack of calcium.
Affected fruits ripen earlier than healthy ones.
The best way to prevent this is with regular and thorough watering. Mulch the soil to conserve moisture and do not overfertilize. Salt buildup will inhibit calcium uptake. Add limestone if soil pH tests below a 6 reading. These are green very well-camouflaged caterpillars which can be up to 4 inches long.