How big a pot do I need for tomato plants?

[Cutandpaste]

I have some Marmande plants and cherry tomato plants. They have really shot up, over a foot tall now. How big a pot do I need for them? I have some plastic pots that are 30cm x 30cm - really quite massive and will use quite a lot of compost to fill. There are six plants in total. Can I plant two in one pot or should I do one per pot?

At the moment the plants are inside, I’m SE and it’s been really warm for weeks. Can I move them outside?

I'd like the answer to this question as well.

People say they need big pots for their roots, but then they grow well in gro bags which you'd think wouldn't work at all

On Friday's GW, I'm sure Monty said 10 litre pot is an ideal size. RHS says 30cm:

www.rhs.org.uk/advice/grow-your-own/containers/may-edible-container-idea

Thanks Kerning, should have gone to the RHS first!

I have planted three of them in the big pots, need more compost for the other three. I’m surprised that 30cm is the minimum size they recommend as the pots seem so big!

I’m not sure about your tomatoes but I’ve got moneymakers and romas. The MM I’m putting in 40cm pots and the plum are going in 30cm. I have made tomato cages for the MM and will stake the plum ones.

Not putting them out till next weekend as it’s going to be freezing again this week.

I would only plant 1 in a 30cm x 30cm pot. But some of my tomatoes are in 20cm pots. I wouldn't go smaller than that. Remember they will end up about 1m high and with several pounds of fruit.

When I plant things in big pots, I usually half fill the pot with garden compost rather than using bought compost for the whole pot.

Ok stupid question alert.
When people say, 30cm pot do they mean 30cm diameter across the top?

I would measure the plant up against your pot, remember when you plant them you are advised to plant as deep as the first set of leaves, ie not just the root ball this means extra roots grow out from the stem allowing the plant to take more nutrients, so allow for this.. Leave a couple of centimetres at the top to allow for watering and a decent amount at the bottom of the pot, allowing for drainage materials eg a layer of polystyrene or broken pot. After a few weeks the nutrition will be coming from photosynthesis and feeding so as long as the roots have room to spread outwards for stability the pot doesn't have to be enormous. Keep up with watering and feeding , seems to be the thing that makes the difference.

I grow my tomatoes in a pvc mini greenhouse thing , it's quite tall and I realised last year (thanks Monty) that the best way to support growing tomatoes was to dangle string from the frame above each pot, attach the bottom end to a cane next to the plant then gently wind the string around the plant as it grew, no need to keep tying it in to the cane.

PS mine aren't going out yet, annoyingly I had started to harden them off as the weather was so nice but the last few days/nights have been so cold and windy I am keeping them in for a bit longer. They are really ready to go though and urgently need potting on, but I am going to hang on until the weekend , they are very pampered, live in a sunny enclosed porch in the daytime , but are brought into the kitchen at night!

Some great advice here, thank you.

7days - I’m assuming 30cm means diameter although my 30cm diameter pots are also 30cm high. Also, a 10 litre pot is 30cm diameter - I googled it!

My plants are now all potted, I’ve given one away as I felt 5 were more than enough? I’m not really sure of the yield?

All plants are in my extremely sunny kitchen, will follow everyone else here about when to move them out!

One final question if I may, I noticed when repotting them that some of the plants now have more than one central stem. Should they just have one or is it ok to have several? I did check whether I needed to remove side shoots and read that it isn’t necessary for determinate types, which I believe both of mine are?

Thank you Cutandpaste

Im a big fan of the b&q orange plastic buckets. I have about a dozen carrots in one and going to put a courgette and tomato plant in others tomorrow . They're just the right size and easily carried if you want to change location

Sorry to hijack the thread, but there seems to be lots of tomato knowledge on here! I've been given two unidentified tomato plants. Is there any way of figuring out whether they are determinate or not?

@tdm1 I wondered that too, just found this:

The determinate tomato plant is often grown in a cage or even without support, as it has a more compact shape. The determinate tomato varieties also produce most of their fruit on the terminal end. The indeterminate tomato varieties have much longer stem growth, which continues to grow until cold weather arrives. They require staking and tying onto a structure to keep the fruit off the ground. This type sets fruit along the stem.

Read more at Gardening Know How: Determinate vs Indeterminate Tomatoes: How To Distinguish A Determinate From An Indeterminate Tomato https://www.gardeningknowhow.com/edible/vegetables/tomato/determinate-vs-indeterminate.htmm_

Mine must be indeterminate, as there are flowers on the stem quite near the main stem

This is so useful! My tomato seedlings are just getting big enough to need re-potting.

@joydivisionovengloves1 thanks for that!

When people say, 30cm pot do they mean 30cm diameter across the top? Yes.

they are very pampered, live in a sunny enclosed porch in the daytime , but are brought into the kitchen at night! That is pampering! Mine stay in the porch at night.But it is an enclosed porch, ie it has a door.

Cutandpaste Removing side shoots is mainly about good access to the plants and keeping a good airflow around. If you don't remove side shoots from an indeterminate, you end up with a jungle, but you still get tomatoes. Several stems seem fine for a determinate.