I have very acid soil, so I add wood ash or lime annually in the fall to mellow into the soil over the winter and raise the pH to a more veggie-friendly level. I don't know when the best time to add would be for you if it is needed. I also add compost and composted manure, sometimes turned in before planting and sometimes as mulch on the surface. I've never added liquid fertilizer, either with raised beds or with in-ground beds, but you haven't told us anything about your soil, so it's difficult to know what is needed. What did you use to create your raised beds? (My beds, whether raised or not, are a combination of native soil, compost and composted horse or cow manure.) Have you had a soil test done? IME soil is always the key to successful gardening, so when have a soil test done it will give you key nutrients, pH, soil texture, and organic matter, usually with some recommendations for needed supplements.

There isn't a "best". There are many many goods ones but no best as it all depends on what your approach to gardening is (organic or not) and what your soil may need and the only way to know that for sure is a prof soil test. Is that possible?

Compost is always a good soil amendment but it isn't primarily a fertilizer. It can provide nutrients IF you have a well established and active soil bacteria level. Manured compost (never fresh manure) is better IMO as it contains more nutrients but the active bacteria (called "soil food web") is still required to make the nutrients available to the plants. If this is in ground those bacteria are there but need several season of work to kick into high gear. If in containers the bacteria doesn't exist unless added regularly.

There are many forms of supplemental synthetic fertilizers available if you aren't devoted to growing organically and the liquids are only a small part of them. The liquids - used per label directions - work well in containers but in in-ground beds are just a quick-fix as they disperse away from the roots fairly rapidly. The dry granular supplements stay in place and decompose slowly slow provide a somewhat slower but longer duration of nutrients.

I don't know what sort of dray granular supplements are available to you in New Zealand but if I were you I'd explore local sources for them. Look for something with a rating of something like 10-10-10 or something with a higher first number for the nitrogen leafy vegetables you are growing, say 15-12-10 or that range. Also keep your eye out for some of the bacterial supplements that can be added to soil so the the compost can work more efficiently.

Hope this helps.

Dave

Hi guys,

3 of my beds are raised up, but still in contact with the ground, with no bottom to them. However one of them is built into some old steps, so doesn't contact with soil, just concrete.

They are all filled with "potting mix", which is quite generic I know.

I would prefer to go with the organic method, but not sure if this is possible with my setup?

In terms of bacterial supplements I have got Mycorrhizal bacteria that I use on Strawberries and Blueberries. Will this help?

Thanks for your help. I have been pretty gung-ho in the past and think I need to take a step back and actually plan things a bit more.

Cheers,

Ben

There's no need to add bacteria to your soil - it's teeming with them unless it's a very salty or acidic soil.

There's no need to add bacteria to your soil - it's teeming with them unless it's a very salty or acidic soil.

I would agree IF the OP's beds had soil in them. As he indicated above, they do not. They are filled with a soil-less potting mix.

Dave