I've got some 4-10-3 that has some very useless instruction saying to use a certain amount per quart of dirt. That's too confusing. I just soaked some bare rooted plants in a diluted mix then planted them. No harm done.

Nutrient usage by plants is usually measured as a function of the amount of N used. Plants use about 6x as much N as P. 3-10-3 has about 8.5x as much P as your plant can/will use in relation to N. The excess P has no potential benefit - only a downside. Excess P unnecessarily contributes to the EC/TDS (salt level) of the soil solution, it raises soil pH, and makes it more difficult for the plant to take up potassium, calcium, copper, magnesium, zinc, and (particularly) iron and manganese. Phosphorous, particularly in excess, is also very destructive of established mycorrhizal symbiotic relationships and can completely prevent new relationships from forming.

The idea that P is somehow more important to root and bloom growth than any other nutrient is a myth, and the only way increasing the amount of P a plant gets can be a plus is if it is/was deficient in P to start with.

It's hardly ever wise to start adding single nutrients or a little of this and that because you heard whatever nutrient your adding is good for the plant. It's only good for the plant if there is a deficiency of that element.

The goal for fertilizing containerized plants can easily be described. You should work toward ensuring that all the nutrients plants normally secure from the soil are in the soil solution at all times, in the ratio at which the plant actually uses the nutrients, and at a concentration high enough to ensure no deficiencies yet low enough to ensure the plant isn't impeded in its ability to take up water and the nutrients dissolved in water. This goal is easily achievable using one water soluble synthetic fertilizer.

Al

This post was edited by tapla on Sat, Nov 15, 14 at 22:11

I can attest to what Al is saying, from my personal observations. Prior to using FP 9:3:6, I was using a "bloom" booster (high P) repeatedly, which started causing lighter colour in the leaf edges and salt built up in my cacti mix at the time. (Now using a gritty mix as well). Since the switch, even before the soil change, I saw little salt built up & plants stayed a consistent colour.
As a one time use, I can't see it doing too much harm though. Just probably not worth it in my opinion.

Best wishes on your juvies :)

A vicious circle - the excess P causes antagonistic deficiencies of Fe and Mn, both of which cause chlorosis. The grower, thinking the plant needs more fertilizer, doses the plants again, which of course only makes things worse.

The fertilizer Anon is using is an excellent choice and a complete nutritional supplementation program in a bottle.

Al

hmmm....Thanks for all the input =D really appreciate it!
what's this stuff good for then? lol!

Yes, I thought the instructions were a bit useless as well =/
glad it wasn't just me. I was starting to think I was missing something.

Good thing I didn't bother. I had no plans to fertilize anything as they are re-pots ranging from 2 weeks ago up till a couple of days ago. Many plants I had defoliated to get at all the nooks & crannies, fighting the good fight against mealies (c. ovata, adenium & aeonium).

In general, I practice no water till showing new growth, but if the leaves feel flaccid & skewer is dry, I'll give a drink.

I had planned that if mix is wet & leaves showing signs of drought, I would dump the potting mix and go grittier, taking that as a sign of disappearing roots =P

So far, I haven't had to do that, but I'm prepared to, given that I used whatever I had on hand as I wanted to use up some stuff (perlite, charcoal, coarse sand etc.) Included in the mix is grani-grit, and micro bark.

If damp, I leave alone for a couple of days & check back.
I hope I'm on track here =) Please let me know if I'm not.

Everyone has put on new baby leaves & I'm getting ready to put them under a shop light for the rest of the season. Currently in a west facing room with triple patio doors (so plenty of light for now) but only just. Here in NY, it was full on night-time outside today at 5:30pm.

I wasn't planning on fertilizing for another month or so. I have Osmocote 'smart release' it's 14-14-14.

I suppose that's safe to apply?
Thanks guys (nudging imaginary rock with toe)
=)