lack of water?

Thank you.

Tomato plants, especially in the greenhouse need a lot of water particularly if it is hot

They have been outside and we have been watering them but clearly not enough.

This is a frequent 'problem' with tomatoes early on in growth, often caused by too much feed before they set fruit. Tomatoes planted in the ground can suffer a whole lot of drought once established, so I'd suspect this is just a physiological problem caused by the compost, which will disappear as they grow on. If they are in a grow bag or a pot, clearly they will need regular watering, but it's best once the fruit are set to give them as little water as possible to ensure sweet delicious fruit. Tomatoes which are overwatered or hydroponically grown are the tasteless ones like we buy at the supermarket from the Dutch polytunnels.

I see, that makes sense thank you. I have been using all purpose miracle grow every two weeks. I wonder, how often should I use it?

Tomatoes are 'gross feeders' so they say (makes them sound greedy!) so I think once the fruit are formed and growing away a weekly or biweekly feed is fine. A little (very dilute feed) and often is better than a heavy feed.

I agre Bertie

Great thank you.