How often do you water your tomatoes?


Nothing beats the taste of home-grown tomatoes, but are you watering your plants frequently enough?

This time last year, I admitted defeat and consigned my tomato plants to the compost bin. The stalks they’d been reduced to were beyond salvation.

My attempts at Grow Your Own had started promisingly. I’d given my dad ‘Montello F1’ seed from the Which? Gardening member trials, and he’d germinated it and potted up the seedlings.

When ready, I duly transferred them into growing bags. But a deluge lasting for several days in early June made the bags sodden. As the plants weren’t looking too happy about the situation, I decided to put them in pots instead.

Shortly after, a family medical emergency saw me rushing off to Venice. Although I’d found the time to water the plants before I jetted off, they were left without a drink for the best part of a week – in the late June heat – before I remembered them and asked the cat sitter if she could water them.

Sadly, it was too late, and when I eventually returned home I found dried-up leaves and stalks instead of tomato plants. They’d clearly objected to the extremes I’d subjected them to.

dead tomatoes
Second attempt

Not one to give up easily, I decided to give GYO another go this year and vowed to be much kinder to my plants. I’m diligently giving them a good soak every evening and, so far, things are looking positive. I have fruit setting and some plants are on their fourth or fifth truss.

growing tomatoes
But reading the test results from a recent Which? Gardening trial, I’m wondering whether I should be watering them twice a day for the best possible yield and the least chance of disease setting in.

The trial consisted of 12 ‘Shirley’ plants grown in 20L pots. One set of three was watered in the morning and evening, another trio was watered once a day, and a third once a week. The remaining three were watered irregularly – between every two and seven days.

Of the four sets, those watered twice a day, keeping the compost uniformly moist, gave the largest yield and best quality fruit.

However, I’m not being too hard on my own plants, as those that were watered once a day in the trial gave the second largest yield and slightly larger fruit. Nevertheless, some fruits did split or had crazed skin towards the end of the test, so I’ll be keeping a keen eye out for this on my plants.

But judging by the pot size used by our experts, I’m not convinced the ones my plants are in are large enough… Oh well, there’s always next year.

How often do you water your tomatoes? What are your tips for achieving a bumper harvest?


We have a new garden so experience is limited. The 30 plants we have are planted into the soil and feature several varieties.

What may have been a good trial was rather ruined with two nights of zero degrees apparently wiping out all but one plant. To my surprise eventually eleven recovered and grew again. New plants have been planted to replace the casualties and our first red tomato is ready for the table.

Watering has been random though we have installed a soaker hose it is not linked to a timer. One has to consider metered water costs compared to the value of the crop. Has this been done in the Gardening Which? article.?

Somebody local has a Personal Weather station which gives me access to temperature and daily rainfall figures which helps in deciding whether to water or not. I would recommend readers go to and see if they have any local.

For Marylebone Rd. I see this station reporting this now.
Elev 30 m 51.52 °N, 0.19 °W | Updated 11 min ago
Partly Cloudy 18.6 °C Feels Like 18.6 °C

In my small village we have three though only the closest broadcasts the rainfall figures which usefully show the time of day and the intensity. Rain at night being more useful than rain during the day.


I wonder if watering a great deal is the answer? My better half has tried three times, to no avail. She has always worried about ‘over watering’ but perhaps that doesn’t apply to toms?


It definitely applies to toms, Ian. That’s why I took mine out of the sodden growing bags in the first place. They really didn’t look happy and were showing the same symptoms as being under-watered.

JE says:
9 July 2017

I use an Easy2Grow kit – 4 large pots with a water reservoir which lasts ( in Scotland, in a greenhouse) a week in hot sunny weather and considerably longer under grey skies. It’s worth the initial outlay as plants are watered on demand so no problems arising from inconsistent watering. I’ve been using this method successfully for 5 years now. I’d never go back to Growbags/ ordinary pots.


Details about Easy2Grow kit here:


I think I might try these next year, JE. Sounds a lot less hassle.


Thanks, Patrick.


I’ve been using these autopots for a few years now for Tomatoes and Courgettes (2 pots per 47l container of water). I live on the Sussex coast – usually they are kept watered for about 2+ weeks but in hotter conditions/fully grown you might need to fill up weekly (outside under eaves facing south). I also use the liquid fertiliser that is sold on the autopot site (which is meant not to clog up the filter) – its a bit pricey so better to buy in larger amounts but it seem to improve the yield/health of the plants.

Gerard Phelan says:
9 July 2017

I noted that the Grow Bags I bought this year (New Horizon Peat Free and Organic) instructed me to make cuts on the underside of the bags to ensure that the bags do not get waterlogged. In past years this has been a problem when I have used my automatic watering system to water the Tomatoes in Grow Bags in the Greenhouse. I have stopped doing that (other then when on holiday) and drench every few days.
I just bought a “The Good Life” Light and Moisture Meter, the moisture scale of which goes from 1-10. Having drenched at 7pm yesterday evening, then at 3pm today, on a hot (30C) and sunny afternoon the meter reads 9 or 10 depending on the plant. The meter guide recommends checking every 3 days and watering when the reading drops to 8, which shows that Tomatoes like their roots very damp, if not wet.
For comparison, the recommended watering level for Courgettes is 6, and for Melon and Strawberries is 5.