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?

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’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.

A long time ago when I used to work on a farm in the school holidays I was engaged in picking and packing tomatoes at this time of the year. There were two very large glass-houses raising thousands of plants and about two hours was spent every morning picking them and getting them ready for delivery to local shops and the produce market. The glasshouses had a trickle irrigation system which kept the light soil sufficiently moist to produce a continuing ripe crop every day for weeks. They were lovely tomatoes with thin skins, soft cores, fruity innards and a real tomato taste unlike today’s shop-bought specimens air-freighted in from all over. The one thing I disliked about that particular work was the abiding smell of tomatoes in my clothes and the green stains on the shoulders of my shirts caused by walking between the lines of stems and being brushed by the leaves. But we were never short of tomatoes.

A friend of mine gives me tomato plants every year and I grow them by the window in my utility room in pots using normal vegetable compost plus Domorite in the water every so often. I keep an eye out for suckers and side shoots and pinch them off, and I don’t let the plants grow too tall either. The three pots are sitting in plastic salad bowls as saucers to avoid overflow and I give each c3/4 pints of water every day. Whatever collects in the saucers is long gone by the next day. I use the tomatoes to make sauces and Delia’s simple tomato soup.

Last year this friend gave me cucumbers and the same method worked a treat, but not Domorite. I also pinched off all the male flowers every day. The tomatoes were so-so, but the cucumbers were delicious. We ate them in salads and sandwiches and I also made chutney.

I got the idea from Allotment Garden on the web, easy recipe, no frills (cucumber and apple chutney). I think you can chutney just about anything anyway? I’ve seen myself chuck in things like an old tomato, carrots, beetroot, dried apricots, to make up the weight in the recipe, all with enough texture and a nice taste to begin with. A great way to get rid of older fruit and veg.

I grow toms in bottomless pots on the greenhouse soil and keep that moist to get the roots down – these, I think, are the roots that like water whilst the ones in the pot like the liquid feed. I use a moisture meter and give a big watering, rather than little and often. When I’ve gone on holiday I used a drip watering system – hose connected to small bore tubing with small plastic drippers to each pot, fed from a timer on the outside tap. that worked well.

I’ve always used the bucket of water and strips of old towelling method of keeping tomatoes moist while
I’m away for some days…soak the towelling and lead a strip from the bucket to the tomato pot, tucked in
nicely. It always kept the plants alive!

Maria G

If you plant basil between your tomatoes it will tell you quite clearly when the earth is too dry and your tomatoes need watering! 🙂

Like JE I use one of the water reservoir systems, the Quadgrow system reviewed by Which recently. I have used them for 4 years in a greenhouse and have had good consistent results. The Which review said that they considered the pots too small, but the roots soon go into the reservoir. Last year I bought some for my mother and she has had success with these, it removes the need for daily watering, although in hot spells they do need refilling every 3-4 days. I think they help to moderate temperatures in the greenhouse with their relatively large quantities of water.

We grow tomatoes in the greenhouse in bottomless pots in growbags, watering once daily. with Tomorite or equivalent after first truss formed. They seem to do all right, the soil in the growbags has dried out sufficiently to welcome more water without becoming waterlogged each morning.

Trish says:
15 July 2017

After many years of sub-standard results, I now grow mine in the Quadgrow system, basically pots sitting on tanks with a capillary feed. The tanks are filled and after the first truss plant food is added, meaning the plants take up a small dose constantly together with however much water they require. Topping up is every few days/over a week, depending on plant size and weather conditions.

I enjoy trying to grow tomatoes that look as good and taste as good as those we can buy. Taste, fine, getting them to ripen at even nearly the same time seems impossible, even in a greenhouse with auto watering and Tomorite applied as recommended on the pack.
One problem appears to be the timing of watering before flowers have set. Too much water too soon, too much foliage.
And has anyone ever worked out how much home-grown tomatoes cost? I suspect we’re paying a premium for growing our own…

We’ve been growing tomatoes in our greenhouse for years. This year for second, but not consecutive, time they are in big pots, actually builders buckets with holes drilled in the bottom. The buckets were all full of old pre-used soil/compost. Some compost was dug out of the middle, slow release fertiliser mixed in then the small tom’ planted. All are doing VERY WELL, watered twice a day by a timed watering system. We are expecting to pick the first next week, about Tuesday 18th July.
Peter Wood, Doncaster.

I grow my tomato’s in 12 inch pots – 3 to a pot and keep the pot in a “bath” or deep tray and keep an eye on the level of the water in the tray always making sure that the tray never runs dry. This way I usually only need to top up every 3 to 4 days I get excellent growth and many trusses and have to make sure I clip the top if I can see the fruit is not going to have time to develop.
My only problem is blight which appears to be dependant on the weather and I can not do much about that

I grow my tomatoes using ring culture. Either buy the ring culture pots, or do as I do. Get large pots, cut the bottom out completely. By husband built me framed beds in the greenhouse . Line it with plastic . Make it about 9 inches deep. Then fill with gravel. Stand the pots on top of this gravel. Fill pots with compost , plant one plant to each pot. Before planting , stake a stick in each pot, so that the plant can be tied to it as it grows . Fill the frames with water. Water each plant regularly until they become established , say every other day. Once you believe that the roots have reached the gravel, you only need to top up the gravel bed once a week, depending on the weather . When it’s time to feed plants , do it through the top . This way the roots never dry out. You can then keep the gravel bed for the following years , as long as you make sure that they are cleaned /sterilised . My husband build the gravel beds to to run both sides of the greenhouse. Hope this helps. The tomatoes won’t crack from lack of water

I have been using the Tropf Blumat system for about 15 years and although fiddly to set up it seems to work. Not cheap but it has lasted. One year I did have problems with tomato stem necrosis because I had not adjusted the system properly before going away and plants were too wet but only one of the two varieties was affected. I water with fertiliser weekly and use home made Bordeaux mixture on blight resistant varieties. This year it is Crimson Crush and Mountain Magic.

wunnus says:
16 July 2017

OK I plant outside directly into the soil… more nutrients and a potentially a larger water supply. I protect them from the desiccating impact of the wind. I water twice a day when there is no rain. I feed with seaweed fertilser. I have 12 plants in a block, all different. None of them the supermarket style of tomato ie high yield. Always pleased with the results.

The truth is, how much water a tomato plant needs varies from day to day depending upon whether the weather is sunny, cloudy, or humid, and day length – how many hours of daylight we’re getting. In his book ‘Tomatoes’, Terry Marshall has a table suggesting that the need varies from a quarter to half a pint per plant on a very dull day to 3 pints on a very sunny day. But he also says that most people tend to over-water, given that the tastiest fruits come from plants kept slightly on the dry side. It really comes down to keeping a regular eye on the plants and using commonsense. I’d just add that before I got my very small greenhouse, I tried using one of the hydroponic systems in our conservatory. Mistake! The system worked very well and we got a huge crop of tomatoes from very healthy plants, BUT they ‘breathed out’ a huge volume of water vapour, making the conservatory very humid. I currently grow a couple of the very early Latah variety outside in big pots, plus a few plants of Olivade and Nepalplus some peppers in the greenhouse.

As seedlings, I water my tomato plants every day or two, depending on how hot (or cold) the weather is. When each plant is transplanted into its final pot, in which it will spend the summer months, I stand the pot in a tray of water, then I just make sure the tray has about 1″ of water in it each day. The tomato plant takes as much water as it needs, and if I can’t get around to watering for a day or two, I know the plant won’t dry out.

Just a snippet from a magazine about a tomato grower fanatic in France.
” A friend who doesn’t grow tomatoes but painstakingly researches and catalogues seeds and plants from all over the world. So far he has collated over 15,000 ( They weigh from 1g to 1.5kg. The smallest are the size of trout caviar. There are tomatoes which have peach like rough skins. The richness of the tomato world is amazing. Last year an elderly man came up to me and shook my hand and said he thought his childhood memories of delicious tomatoes must have been a fantasy but now he had discovered that tomatoes were really that good when he was growing up.” Connexions

Incidentally he gardens organically and recommends nettles cut and placed at the bottom of tomato plants as they produce nitrogen.