Fertilizing

[Higgs Boson]

That has always been my weak point. I know (barely) not to fertilize when plants are dormant, but I always stumble when, e.g., to fertilize my roses after mid-January pruning.

I have two young fruit trees (Plum and Apricot) which are just shedding their leaves, and two blueberry bushes in large pots, one of which is confused enough to be blooming and setting fruit.

I also have growing "winter" vegetable crops that, I assume, it's OK to fertilize: Peas, beets, carrots, green onions, bok choy, stuff like that.

Is there ONE comprehensive "when to fertilize" rule? Geared to my mild "Mediterranean" climate -- So. Calif coastal?

TIA

HB

[David Hare-Scott]

It's very hard to say it all in one rule that would always be applicable.

Fertilise when the plants need the minerals. That would be when the plants have reduced (or will soon reduce) the available minerals below its requirement AND when they need them, that is when they are (or soon will be) growing strongly. The type, amount and frequency of application will depends on your soil, the plants and the conditions. Over fertilising can be as harmful, or more harmful, than under fertilising, this error is easy to make with sources that are concentrated such as synthetics or fresh chook manure.

David

[David E. Ross]

Roses like a lot of nutrients. I feed mine monthly from when the leaf buds begin to swell until mid-October.

I have only one deciduous fruit tree, a peach. It gets fed once a year, when flower buds start to show a little color (before they open).

My dwarf citrus is mostly in large pots with a fast-draining mix. That means nutrients leach away quickly. I lightly feed my citrus every three weeks from the beginning of March until the beginning of October.

My camellias and azaleas get fed once a year, when they are through blooming.

Everything else -- including the grass in back -- gets fed once a year, in March or April.

Excess fertilizer promotes excess foliage, which requires excess water. Without trying to have a drought-tolerant garden, I'm trying to conserve water. Thus, I avoid feeding more than once a year except for the roses and citrus.

[Father Haskell]

Balanced (5-10-10, 10-10-10, 20-20-20) with secondary and micronutrients when the plant wants it -- leaves will show yellowing or spotting. Higher N is used for foliage, P and K for fruiting and flowering. Synthetics (Peter's, Miracle-Gro) are faster release than organics, less likely to burn or be overapplied HOWEVER organics can get you in trouble if excessively overdone. Fish emulsion is wonderful fertilizer, but excess, especially in soggy soil, breeds fungus gnats or other pests. Root damage from gnat maggots impairs nutrient uptake. If infestation isn't obvious, you end up pouring on more fertilizer, which makes the problem worse, making you pour on still more fertilizer, breeding still more maggots. If you need to resort to bug killers, your "organic" plant food is no longer so "organic."