How to substitute potash fertilizer

[Everett]

Hello!

I have a lot of seedlings that are almost ready to plant out into my rooftop container garden, and I am wondering... If I use a premium compost as well as some well-rotted manure or perhaps worm castings in my potting mix, can I skate by without a potash-heavy fertilizer?

I am planting tomatoes, carrots, cucumbers, eggplants, peas, onions, strawberries and an assortment of salad greens. I only have some liquid fish fertilizer (6-1-1 or something like that), some phosphorous-heavy bat guano. They have done wonders for my roses, but I understand that some plants require a bit more potash. I also started a worm bin a few months back but have yet to harvest from it.

 

[AndrewB]

Hi Everett, absolutely, I've grown all of those plants successfully in pots without fertilizer, compost & mulch is all you need, the manure & worm castings would be a bonus.

 

[Everett]

@Andrew Just what I wanted to hear! Thanks.

I know a lot of those plants have fairly deep root systems.. do you think I would be okay in a 35 cm high, 30 cm wide pot for the deepest of those plants? (I should mention, I'm growing compact shrub varieties of the tomatoes, cucumbers, and peas.)

 

[AndrewB]

For carrots, peas, strawberries & greens the 30cm pots would be ok, I used 50cm for tomatoes, eggplants & cucumbers.

 

[Everett]

I'm envious of your container garden! Thanks for the tips, I'll make sure I put the tomatoes/cucumbers/eggplants in bigger pots.