Sowing in toilet rolls is not a good idea
I used to start seeds in toilet rolls, or peat pots. Then I discovered that seedlings grow much less well in them.
Sometimes that happens. You think you have found a clever, inexpensive solution, and you tell anyone who will listen. I even included it in my first book.
Then you discover that it was not so clever after all and that you would have been much better off doing something else. Ouch.
Just look at my tomato plants
At the end of March 2018, I started my tomato seeds in vermiculite:
Two weeks later, I moved the seedlings into toilet rolls filled with MM-mix.
But I did not have enough rolls, so I put some of them in the pots my violas had come in.
I watered them carefully, gave them plenty of light and the plants grew well.
But then:
The plants in the pots began to grow much better than the ones in the toilet rolls. And the difference was not small:
Gulp.
Toilet rolls may be cheap, but they are clearly not a good idea. So I am sorry if you followed my advice.
Incidentally, the same applies to starting seeds in peat pots.
What now? Throw them away?
No, of course not. As I said, I did it this way for years and we harvested masses of tomatoes every year.
So if you have already done it, you can move the plants into a larger pot. They will still have plenty of room to grow.
It is a good idea to repot tomato plants anyway. You can plant them as deeply as possible in their larger pots.
Part of the stem that was above the soil will then be covered with MM-mix. New roots will grow from it, helping the plant become larger and stronger.
When can they go outside?
Tomatoes need at least 18°C to grow. Below 15°C, they stop growing, and below 10°C they will eventually die.
That is why tomato plants started indoors should not go outside until the end of May. The same applies to courgettes, cucumbers and pumpkins.
PS: We are still learning and discovering better methods. That is why we have used a slightly different way to start seeds indoors since 2020. Read more about it here.