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Planting tomatoes outside, how tall should they be?

Hi all, 

My tomato seedlings were potted into 10cm pots around 2 weeks ago. They're now around 12cm tall. Im worried they're not getting enough light on my small kitchen windowsill, are they too small to start potting them into their permanent large pots and hardening them off? (I've also noticed that some of the leaves have started to yellow, I'm not sure if this is a consequence of the poor light?)

Their location for permanent growing over the summer is in very large pots on a balcony in Newcastle. Not sure how such little plants will cope with windy days. Any thoughts? 



  • If there is still a risk of frost keep them under cover at night, but you could expose them to more sunlight in their current pots during the day on the balcony. 

    Though they might be etiolated, they'll need a vegetative feed if you have potted them on into a low nutrient growing media. That's a general purpose balanced plant food, not tomato food which is high in K to promote flowering and fruiting

    I was just going out to the botanic garden today after a bit of sunning myself. I checked I had everything, sunglasses, hat, sunscreen,. As soon as I got out the door - hailstones!

  • wishbonewishbone Posts: 44

    Hi Cat

    You could try putting them in their final home with bottle cloches to protect them. Just get empty clear plastic bottles and cut the bottom off, put a stake in next to seedling through the neck of the bottle and bury the edge of bottle a little into the soil which will stop it blowing away. I`m sure they`ll be happier outside and when they are a little bigger you can harden them off by removing the bottle cloches. Good luck!

  • PalaisglidePalaisglide Posts: 3,414

    I live in Stockton and the outdoor plants can go out now, we should not get another frost, fingers crossed. You say a balcony, fasten a wind shield to the rail on the prevalent side and have some fleece to cover lightly on very cold days. Mix some compost with granular fertiliser and dress the top of the pot, water in. Use tomato fertiliser when the first fruits set. I have a greenhouse for the main crop but have outdoor plants too, with some shelter they always crop well, the grandchildren love to pick them straight from the bush.


  • ItalophileItalophile Posts: 1,731

    Cat, they're big enough to plant out in their final homes. The advice about protection is good. It all depends on your temperatures. Wind won't bother them if they're staked and tied up securely. The yellowing could be lack of light but, more likely, overwatering. When they're in their pots, let the mix dry out between waterings. The mix should never be permanently damp.

  • Cat FleetCat Fleet Posts: 15

    thanks for the advice everyone. I had plastic bottle cloches on last weekend when they were outside, they got a bit steamy and wasn't sure how good the humidity would be for them so i ended up taking them off but i might try it again when I've left the soil to dry out. 

  • ItalophileItalophile Posts: 1,731

    What sort of day and night temps are you having, Cat?

  • Hi Cat, I'm in Durham and my plants have been outdoors now for 10 days & nights. Going to risk it and plant out in the raised bed tomorrow. Best of luckimage

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