Ash for tomatoe plants

[Seagull]

I am growing tomatoes for the first time this year, in pots on my balcony. I read that you can use ash to fertilize them. Can you just dump ash from a wood fire on top of the soil, or will it leach and turn into lye? How much and when should be used?

[the.fee.fairy]

I mix some in with some compost and use it as a top dressing.

Or...over the winter, i put ash in my compost heap so that the nutrients are in the compost, which also gets used as a top dressing.