Potash, in this context, is potassium. If you have ever seen NPK on a fertilizer, the 'K' is potassium, 'N' is nitrogen and 'P' is phosphorous.

You could try adding compost to see if it helps.

Another idea would be to buy a balanced NPK fertilzier. Or you could add some wood ash (which will supply K and also raise the pH) as well as an NP fertilizer.

If you buy commercial fertilizer, follow the instructions. If you use compost, add as much as you can and mix it in to the topsoil.

McKenzie

N is always low, that's a given.

Compost, compost, compost. Oh and did I mention...compost.

The better the quality the better the results.

When - as often as possible. Minimum of 2x a year. In spring before planting time and again in the fall when putting the garden to bed. Used as a side dressing on the plants throughout the garden season is even better.

Dave

Can I add it now here on Long Island where it's 20 degrees?

Where I live the ground doesn't freeze. I think you will have to wait until the ground thaws to add anything. As digdirt said, "in spring before planting."

--McKenzie

You can it it is available. It won't hurt anything as it will just lie there until the weather warms. But if your zone 7 is like mine we get periods of warmer weather off an on until spring and during those periods the compost can activate and have beneficial effects.

If you decide to lay on several inches now then plan to add more approx. 2 weeks prior to planting time.

Dave