Fertilising Program for Zone 10a

[chris.oz]

Palm wisdom says dont fertilise your palms in winter. I have many palms that actually grow during our winter...so its not that bad.

Has anyone in zones like "cool" 10a... here in Melbourne tried slow release over winter?

I hardly fertilise my palms at all. I am on a poor quality sandy soil, fertiliser tends to leach out very quickly and I am a bit afraid of

burning the roots with excessive applications in spring.

I think I may have to start fertilising a lot more to get the growth and to correct nutrient deficiencies .

Question is, would l all year round slow release in moderate quantities with extra spring fertilising be a good strategy?

If not, whats the best fertiliser for sandy soil ?

[MattyB]

First of all, I think that all year round with a moderate slow release fertilizer and extra applications in spring and summer is perfect. We're in a cool zone 10 here and palms like Archontophoenix, Rhopalostylis, Ravenea, Pritchardia and many others, continue to grow through winter and benefit from having food available. I hold off on marginal palms that pretty much stop growing when it gets cold.

[gsn]

Chris,

As Mr. Matty B once said "if it's growing I'm throwing!"

I live in 9b/10a coastal east central Florida.We have fairly sandy soils here also,some loam. I fertilize with slow release 4 times a year,December(which is the beginning of our winter) March,June,and September. The way I see it nothing except the really tropical stuff quits growing here in the winter. I also think the winter (December ) fertilizing helps with cold hardiness,brings up the salt content in the plants.The only caveate to winter fertilizing is the chance of an artic front dropping temps below freezing which can burn NEW growth.

Having said that at least for me fertilizing in the winter has more advantages than disadvantages.

[chris.oz]

Thanks Guys,

Thank god we dont get Arctic fronts here. So we just dont get below +2. At least not in the last 6 years.

I think the conventional palm wisdom is to hit the palms with a big slug of fert when the warm weather starts.

This is from virtuall a nil fert situation to maximum in one hit.

Like you Matty I find that some palms still grow over winter and may benefit from some gentle fertilisation.

I will give it a try and see how we go.

Thats unless someone else puts in a caution ???

[kahili]

Not living in a zone 10, I can't speak to weather conditons especially, but I can add some info on slow release ferts that may help you decide on when to fert and what to use.

The sulfur coated slow release ferts will start to release at around 45 degree soil temps. I am not sure at what temps palms have to be at to start utilizing fert, but I would imagine that a sulfur coated fert would release at or below the temps that the palm would use it. So if a palm needs to be at 50 or so degrees to start using the fert, then the sulfur coated ferts will work in the winter. They have varying total time release ferts-I use one in the winter for annuals that is gone in 5 months. So if your soil temps drop that low, then this would possibly be a good fert to use for the winter. If you add it in October, its gone by the end of Feb etc, and then you can safely add another kind if you want knowing that there will not be soluble salts buildup. Sulfur coated ferts are also about a third of the cost of a poly coated fert. Because they are coated in sulfur, they can lower the PH of the soil short term ( a few months, usually), its been my experience that its around a few tenths of a point.

Poly coated ferts don't start to release until the soil temps are much warmer-about 60 degrees to get going and really start to release at around 70-80 degree soil temps. So, for a lot of people who live in the lower zones, they are useless in the winter. One of the upsides to a poly coated slow release is that some of them have at least 50 % nitrate nitrogen which is good if you are using it in a container and are using a soiless mix as your base for the plant. Soiless mixes don't do as well with a fert that is entirely ammonical or urea based nitrogen. I have a lot of palms in containers so this matters to me. In the winter, I use a liquid feed that is mostly nitrate nitrogen for the palms that are in the grhouse, and then switch to a poly coated when they come out in the late spring.

Whenever you use a slow release (esp a 100 % slow release), there is never a "maximum" hit of fert to the plant. These ferts are designed not to release all at once, so you can go from nothing to adding a slow release and the plant wont be negatively affected at all.

Also-both the poly and sulfur coated come with micro nutrients in them.

Hope this helps.

[SubTropicRay]

I believe the salts in fertilizers make the palm slightly more freeze/cold tolerant. Most palms are not severely affected by +2C temps but some marginal ultra-tropicals can suffer damage. I use a slow release fertilizer and make it a point to do so every autumn.

[PalmGuyWC]

When the maximum temps. fall below 50F (10C) at night I've found that most palms are unable to absorb neutrients, and you can burn the roots with fertilizers. I live in a zone 9 and about the middle of Nov through May the night temps fall below 50 F, and there is almost no detectable growth on my palms. I don't fertilize in the Spring until I see some growth.

Dick

[palmtreesforpleasure]

Hi Chris

If you can get tea tree mulch try it mixing osmocote exact 9-12 months (mostly underneath). Tried this last autumn and had the fastest growing 12 months ever. Daryl suggested trying it and has been a great success (tea tree mulch) My soil was old and had gone silty, the mulch has converted the soil to being aerated and full of worms as well as creating warmth in the soil through winter.

regards

colin

[gsn]

  PalmGuyWC said:

When the maximum temps. fall below 50F (10C) at night I've found that most palms are unable to absorb neutrients, and you can burn the roots with fertilizers. I live in a zone 9 and about the middle of Nov through May the night temps fall below 50 F, and there is almost no detectable growth on my palms. I don't fertilize in the Spring until I see some growth.

Dick

Dick,

It may be the case that your palms stop growing when the maximum AIR temp fall below 50F.

But it is the SOIL temp which would determine whether or not a palm can take up nutrients.The soil temp is not going to drop as fast as the maximum air temp,(it is going to be warmer)at least in a 9b/10a zone.