when is it too late to fert?

[Jovary]

Ive been on the fert rig all week. I know its kind of late but my boss sold alot this year and weve been real busy with IPM.

Today I had a client tell me that it was too late to fertilize. She said youre not supposed to fert after June 15 because the new growth would not over winter as well. I told her that Ive never heard that and it was a slow release fertilizer and she let me continue.

Is that true? When is it too late to fert?

 

[Jon Denver]

Most tree's produce a predetermined leaf mass per season. When you fertilize what you really do is increase internodal spacing (the space beetween leaf nodes) and leaf size. Oak's are great examples of this.

What causes late season weak growth that may not harden off in time? Late season pruning! This also reduces energy storage in the rootzone over winter which can lead to a weak next season of growth. Fertilizing into the fall increases root growth and storage.

However if the tree is well established in the ground it probably does not need much fertilizer.

 

[Dadatwins]

A soil test should be done prior to fertilizing to determine what is needed. By randomly dropping fertilizer just because you sold the job is not helping your customers or the trees.

 

[John Paul Sanborn]

Depends on where you are, if you are in an urban area, you can guarantee that there are deficiencies in available elements.

:angrysoapbox: (could I get just a soapbox smiley? ) :rant-mode:

That said, I think most companies just squirt NPK which causes more problems then they help when working with more mature landscape inventories. If using a broad spectrum, low N product derived from organic material one can apply it once a month. The Greenies with compost products are doing this.

Sufficient N and H2O can stimulate a second flush of growth, but then just H2O and good temps can do that. Water is the biggest limiting factor of all, with the second being free O2 in the soil. (ie compaction or water saturation creating anoxic conditions is a bad thing. From my reading the lower limit for free O2 is between 6 & 10%, where somewhere around 15% is optimal.)

I am with the school of thought that when treating trees in an urban environment it is good to provide the broad spectrum of needed elements all season long. This is so that the plant will have them there when conditions are right for it to grow its springwood, fallwood and any flush of growth that the weather allows.

Since most landscapes do not have a any, or deep enough, organic layer to provide a for the nutrient cycle found in even a remnant forest ( most of those are problematic due to the introduction of nightcrawlers, but that is another soapbox to climb on) everything is needed from C HOPKINS CaFe....

I could go on and on, but basic Plant Pys is a semester course...