Tomato watering dilemma

zakthecat · May 2020

I know this will be a subject that has probably been brought up many times on this forum, but when I've tried to do a search I don't seem to find an answer to my specific question, ie how do I know when my plants need watering?

I've just returned my plants (three varieties of tomato, two varieties of sweet peppers, aubergines and jalapenos) to my 6' x 4' greenhouse after bringing them inside for a few days during last week's cold snap. I just really don't know how to tell if/when they need watering. I bought a moisture meter thinking this would tell me, but if I went by this alone they would hardly ever need watering, and I was getting concerned that they don't seem to be taking up any water at all. I know the meter works because I left it in the pot once while I dribbled a little bit of water in and the needle did go up, but I can't help questioning the accuracy of it.

So - is there a very general guide that I can use. I did read somewhere that your finger is the best moisture meter but I would welcome a bit of clarity. Also, do I water with the rose on or do I just water straight onto the compost round the base of the plant?

Thanks to all.

Pete.8 · May 2020

If I have something in a pot I get in the habit of feeling how heavy the pot is to determine if it needs watering. A pot full of wet compost weighs a lot more than a pot of dry compost - you just need to get the feel for it.
I grow tomatoes in the ground but peppers/chilli and cucumbers are all in pots in my greenhouse.
My cucumber is in a 22L pot (so a big pot) I just lift one side to judge if it needs watering.
You'll soon get the hang of it.

The other option is the finger test - poke your finger into the compost a couple of inches - if it's dry - give some water.

Try to water at the base of plants and try not to splash the tomato leaves with water. I don't use a rose when watering

Plashing · May 2020

You could cut the bottom of a plastic bottle and push the neck end into the soil and fill it up then if the bottle is empty,you will know it needs to water again,I have found it very helpful,also you can feed them the same way with liquid feed.I use that method for my courgette's and squashes outside,some people use plant pots as well pushed in.

zakthecat · May 2020

Thanks for the great advice. I've seen some spike things that you replace a bottle top with to supply a constant drip feed to the roots but I think they're more for when you go on holiday (fat chance of that in these worrying times). When you're new to something you want to know exactly what to do, but I guess experience is always the best teacher. I shall now go and test the weight of the pots and poke my finger into the compost and use my judgement.

Fairygirl · May 2020

I think @Pete.8 has covered that very well.
Tomatoes tend to do better with less frequent watering, but the most important thing is consistency in your watering. It's when you leave them for ages and then drown them every day, that problems occur. I only grow undercover, and that can often mean more vigilance. I'm not sure those meters are great - I think if you get used to working with your plants, that's a better method. They won't appreciate sitting in damp compost all the time, especially when they're small.
You'll get a feel for it the more you do it though

I think squashes and courgettes need a bit more watering than toms though, so the advice already given is great.

Good luck anyway - all good experience

strelitzia32 · May 2020

Overwatering is a really common way to negatively affect a plant, killing it through kindness. You'll be surprised relatively how little water tomatoes and chillies want. It's absolutely fine and good to let the compost dry - but not completely! Flood and drain usa usually better than constantly damp (fur chillies etc).

The tips from pete.8 are spot on. You'll also get used to telling what your plant needs from how it looks and feels - dark green leaves vs light green to yellow leaves indicates heading towards too much watering. Feel the leaves, are they stiff or soft? Limp leaves means desperate for water! Brown plant on the ground, too late ;-)

mrtjforman · May 2020

When I grew tomatoes I liked to add perlite to the compost. The compost in tomato grow bags is extremely compact and can stay soggy for months (literally), the perlite adds drainage so you can water more, the water can drain easier and the compost won't stay overly soggy for too long. Since I like to overwater I need to add more drainage to most my pots.
The downside to this is they will then need more watering in the hight of summer when they really start to drink lots.
The moisture meter if it works should be a good indicator though or like pete says liftnig the pot is one of the best methods.

If the plants are growing well I wouldn't worry too much.

zakthecat · May 2020

Thanks everyone, I really appreciate the advice. Because I'm quite new to all this I think I'm a bit like someone who's just had their first baby - constantly fussing and worrying about everything. Sometimes I wonder how any plants manage to survive in the wild where everything is just so random.

B3 · May 2020

The best moisture meter is your finger😊

GemmaJF · May 2020

zakthecat said:

Thanks everyone, I really appreciate the advice. Because I'm quite new to all this I think I'm a bit like someone who's just had their first baby - constantly fussing and worrying about everything. Sometimes I wonder how any plants manage to survive in the wild where everything is just so random.

They survive because they want to grow! Our job is not to make them do it, it is to make sure we don't do things that prevent it!

Tomato watering dilemma

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