pot sizes for tomatoes

[grasser]

wat size pots will i need to gro tomatoes n its my first time growing them need all the help i can get my plants are about 9 inches tall now will i be able to put them in there final pot now or will i have to pot them up in stages
thanks john

[SarzWix]

The 'Tomato Pots' you can buy in Garden Centres or DIY shops are 5 litre capacity. I would say that these are only just big enough - the tomatoes will need watering twice a day in hot weather in this size of pot, and the plants will be too top heavy to keep outdoors without falling over all the time! After a few years of experimenting, I would say that for cordon tomatoes (vine/single stem) you want a minimum of 10 litres (supermarket flower buckets are ideal size), and for bush or outdoor types I'd go bigger than that - patio container size. It depends how much time you have for watering (and whether we get any sunshine or not...!)
As for potting up, what size pot are they in now? Are the roots coming out of the bottom? I'd be tempted to just go up one or 2 pot sizes, they're better in a smaller pot til the first flowers start to form or they'll grow loads of roots & foliage and forget to flower!

[queen of the cobs]

definitely move them up to a slightly / somewhat bigger pot a couple of times before they go into their final big pot.

[Cutecumber]

The only tomatoes I grow in small pots (about 12 litres) are tumbling bush types outside.

There is more than one problem with small pots - by which I mean those less than 15 litres...

If you are growing cordon tomatoes - the ones which you pinch out and grow upwards - how do you support them? Small pots make tall plants very unstable if you just stick a cane in the pot. You are going to need to tie them to some kind of semi-permanent framework to stop them falling over.

If you are growing in a greenhouse, particularly a small one, it is very hard to keep the temperature down in the summer. Very hot conditions will mean it is virtually impossible to keep the plant in such a small pot adequately watered. You will need to be on hand to check them through the day if temperatures climb into the 30's. By 40 degrees they just stop growing, and the pollen can fail. This applies whatever size pot the plant is in, but in a larger pot you can keep the roots cooler which is an advantage. Even outdoors in a warm UK summer you will need to water twice a day.

So, the smaller the pot and the larger the plant, the trickier it will be. Not impossible, but tricky. Try and "stop" the plant (cut off the growing tip) once you have a few good trusses of fruit - say about four if the fruits are large. This will help a lot if you have small pots.

I've tried a variety of container sizes for tomatoes and currently would choose 15 litres for a small-fruited bushy one (like Tumbler), 20-25 for a standard cordon (like Moneymaker), and 25+ for a large-fruited beefsteak (like Big Boy).

It's too hot in my greenhouse for most of the summer so all my toms are grown outside. Unfortunately, it's windy so the plants lose additional moisture through evaporation, but they do seem to prefer the temperature outside - even in last year's summer!

[greg77]

my greenhouse is small and i had asked earlier for any opinions on why i got only the first two trusses producing good toms and the top three pretty much failing.do you think they are struggling with the heat.

[kethry]

greg77: yes absolutely.. even in the really awful summer we had last year, if i didn't get to the greenhouse to unzip the door (one of those plastic jobbies) then the temp would be close to the 40s in there.. even with the door open it would regularly be in the low 30s, and that's in an awful summer with not much sunshine. you can buy thermometers from Wilkinsons and places like that quite cheaply: i would recommend buying one and stringing it up. the only tomato i grew in there last year was tumbling tom, and that was by accident: i stupidly didn't put drainage holes in one container that had the tomato plant in, and of course, with the amount of rain, it ended up swimming for its life! So i moved it into the greenhouse to dry out, and i - amazingly - got a small crop off it.

HTH

keth
xx

[Cutecumber]

I asked about the greenhouse temperature thing when I first came onto this forum last year.

My garden is windy, north facing and the greenhouse gets some shade most of the day... and yet temperatures easily hit 30 in the spring and 40 in the summer. With all the windows and door open I can just keep it at about 38 if it's really hot outside. Some people didn't believe that in this could be possible in the spring, but I have since found that other people experience the same problem. I have tried paint on shading and green shading net, but it's not great. I find that I can only grow aubergines, chillis and cucumbers in the greenhouse through the summer - tomatoes don't do well. Last year, of course, they may have loved it!!

The explanation seems to be that smaller greenhouses - ours is about 8 x 10 ft - just can't get the air through them as well as larger ones.

I highly recommend getting a maximum-minimum thermometer for your greenhouse and paying a daily visit to record and reset it. You can also get radio-controlled remote thermometers with an indoor receiver which makes life a lot easier.

Finding out the temperature range may help you work out why some plants are happy or unhappy in there.

[veg4681]

I find that I can only grow aubergines, chillis and cucumbers in the greenhouse through the summer - tomatoes don't do well.

The explanation seems to be that smaller greenhouses - ours is about 8 x 10 ft - just can't get the air through them as well as larger ones.

Frankly mighty good news that greenhouse may be too hot for tomatoes, just means more space priority for aubergine, pepper and cukes. I hugely resent tomatoes taking up that space otherwise.

If you rate your greenhouse as smallish, imagine mine is only 6 by 2 feet . Definitely no tomatoes in there!

[allotmentlady]

I have decided that in one greenhouse we will grow tomatoes and the other greenhouse we will grow peppers, aubergines etc.......we have an autovent which is a godsend and we replace one glass panel in summer with a mesh guard to allow aeration in the glass greenhouse, it works.

[mrdinkle]

That is interesting. My tomatoes did real bad last year outside against a south facing wall. but it is windy and wet here *most* of the time.

I have two of them 6 by 2 palram greenhouse and was gonna put a couple in one of them - perhaps not after reading this?

[Snadger]

..............I highly recommend getting a maximum-minimum thermometer for your greenhouse and paying a daily visit to record and reset it. You can also get radio-controlled remote thermometers with an indoor receiver which makes life a lot easier.

Finding out the temperature range may help you work out why some plants are happy or unhappy in there.

I managed to pick one up from Wilko's for £4.99......the cheapest I've seen them!

[mrdinkle]

I got one from wilko too and managed to drop it the other day, so need to get a new one.

[heebiejeebie]

Don't mean to hijack the thread but it didn't seem worth starting another! I just acquired a plastic greenhouse and planned to grow tomatoes in it - I have two questions:

(1) They're bushy types. Will it be ok to go from 3" pots to 6" pots then into half-growbags?
(2) On hot days, would it be OK to move them outside the greenhouse if it gets too hot in there?

Previously I have planted them from 3" pots to outdoors with no problems other than blight

[Cutecumber]

Answer no.1: yes, sounds ok as long as they are the small fruited bush types.

Answer no.2: yes, but how would you move the growbag with the plants in it? Individual pots would be easier.

[heebiejeebie]

I'll be cutting the growbags in half around the "waist" and standing the two halves up on their ends so one growbag = two tomato plants and a few small lettuces/basil plants around the edges. I can lift half a growbag with plants in. Couldn't shift a whole one!