Watering can be a tricky business when it comes to tomatoes grown in containers. However, if done properly, correct watering can help avoid Blossom End Rot and create a healthy root structure to power the plant more effectively.
The first aim should be to keep the entire root area moist.
The reason is that roots are only able to feed from areas of soil that are moist.
If half the compost that your plant is growing in is dry, food uptake may also be reduced by half.
If you’ve ever tried to water a pot plant that has very dry soil, you will find that the water runs straight through and out the bottom of the pot, leaving the soil almost as dry as before the water went in!
This can happen to areas of soil in containers without the gardener realising what is happening beneath the soil surface.
If you water from above, give the soil a thorough watering once a week (depending on the weather), then allow to dry until just moist. Keep the soil like this by watering moderately until the next thorough watering.
The smaller your container, the more regularly you will need to water.