Growing tomatoes in pots

For tomatoes, I have used pots and grow-bags as experiments the last couple of years, they are much more difficult to water compared to growing directly in the soil. I used the biggest pots I had, 42L but still had problems with blossom end rot and weak plants (compared to soil grown).

One year I tried grow bags, and doubled them up, i.e. one bag on top of another (with the plastic cut in-between) to make one big bag so as to get extra depth for the roots, but again I had the same watering issues as with pots.

I also used an Octo-Grow system from greenhousesensation for about 4 years but gave up on that for various reasons, whilst they are great for holiday watering I had lots of problems with salts accumulating in the reservoir (coming from the fertilizer mixtures supplied), eventually I had a couple of modifications supplied by greenhousesensation involving draining and flushing during the season which turned out to be quite time consuming. I think the 11L pot size is OK as the roots go deep into the reservoir, but the spacing is too close in my mind, although you can train them away from each other. I also had issues with the root system clogging up the supply water feed and float system and the reservoir dried out, again I had a retrospective modification supplied from greenhousesensation which never completely fixed the problem. The biggest issue was the loss of space, the reservoir and 11l pot on top means you lose a good 24" at least so the first truss is half way up the greenhouse already. So I prefer growing in the soil where you can plant really deep and gain an extra couple of trusses' growing space.

The issue with growing in the soil is that pathogens/diseases build up over the years so I have to change the soil each year ( a big task) or as recently I've been using grafted plants. The rootstock has resistance to the soil borne diseases and gives more vigour to the plants. So that's the method I'm using at the moment - it involves a fair bit of extra work early in the season to do the grafting but for me it works pretty well.

Cucumbers seem to be more forgiving than tomatoes so I grow these in large pots (42L again) and never have any trouble with them. However growing in the same greenhouse with tomatoes does need some compromise as cucs need humidity and toms hate that. I have a separate smaller greenhouse just for my cucs for that reason. Prior to that I used to partition off with a plastic sheet to make two different growing environments.

I have a drip watering system set up on a timer, so apart from feeding and picking I have little to do at this time of year.