Citrus Growers Forum

laidbackdood · Posted: Fri 29 Jul, 2011 3:31 am

Wow...heavy stuff Millet and way over my head Laughing

What i am suggesting here is a bit off subject and more relevant to young trees and up.
My two cents worth=From what i know soluble fert doesnt remain viable in the mix for long ie its nutrients are not there for long for the plant to take it up....Slow release ferts have the advantage in high rain areas like where i am in Auckland as i could feed with soluble fert and then it rains the next day and washes it straight out.By using slow release a small amount of food is available everytime you water and usually each capsule is consistent with its nutrient profile........so if you were to go away in early spring there will be some nutrients there available should it rain.Ad to the fact that rain is organic in nature...your plants will always prefer rainwater to tap.
There is a greater risk of root damage if you fail to water your tree first before the feed with soluble fert...something most manufacturers fail to mention on their instructions...I am sure many gardeners will have burnt the roots on container grown plants Due to watering with soluble fert straight up.
Soluble feeds would be very good in spring/summer time when there is less rain to flush the nutrients out and food is in high demand for spring bud break(especailly nitrogen)......where i am....I use slow release fert with millets suggested formula 5-1-3 npk plus trace..I will foliar feed with new spring growth and feed soluble then but the rest of the time,just the slow release plus mag fillings/gypsum.This procedure suits my climate but i dont know about yours. Wink

danero2004 · Posted: Sat 30 Jul, 2011 5:29 am

Millet wrote:

What actually is "fertilizer burn"? Fertilizers are salts. These salts are not unlike table salt, sodium chloride, except that they contain various plant nutrients. When a salt is added to water, osmotic pressure of the solution is increased. For a plant's root system to take in water, the water must pass through a root cell membrane. Water can pass through this membrane ONLY when osmotic pressure of the solution inside the cell is higher than osmotic pressure of the solution outside the cell. Water moves from a solution with low osmotic pressure into a solution with higher osmotic pressure. If the osmotic pressure of the solution becomes higher (as a result of soluble fertilizer applied) than that of the solution inside the cell, water cannot enter the cell and, under severe conditions, may move out. This results in damage to, or death of, the cell. When root cells die, the whole plant is damaged or may die. The end result is termed "fertilizer burn".(taken from Plant Production In Containers-II) - Millet (547-)

Talking about salts and fertilizers I had one problem and still have it with the ratio from different sellers.

I have a citrus fertilizer wich I say covers the needs with the ratio written on the bottle is 6-3-6 and trace elements and one from Jack's/Scotts wich is 23-6-10 and trace elements so here is the problem:

Isn't it the number the percentage of that Nor K or P like say 23 means 23% N , well if so one recommends using 4g to one gallon of water and the other in the bottle say 15 ml to one gallon of water .

Seems easy but it is not , everyone of them say not to overfertilize but isn't it weird that in order to achieve 250 ppm N from the bottle I should use much much more than the recommended use .

Both say to use at 1 week schedule.

Also on the bottle is written that it will acidify the soil to maintain the Ph level at the right one , and the Scotts doesn't say anithing about the PH level.
Is the N the key factor to increase or dicrease the Ph level ?

Thanks

Stoddo2k11 · Posted: Sat 30 Jul, 2011 5:51 am

Most N in fertilizers would have zero effect on the pH. pH is effected by acids and bases.

Nitric acid would affect the pH (pH down)
ammonia (NH3) would also affect the pH (also ammonium)

Remember the air is over 70% N but in N2 form its unusable to plants. This means the role of fertilizers is to get a usable form of Nitrogen to plants (N03, NH3), also look up the role of nitrogen-fixing microbes.

Edit: I am looking at some nutrient bottles and they do use some N from ammoniacal form although small (one nutrient bottle says 0.25% ammoniacal nitrogen and 3.75% of nitrate nitrogen). This is a hydroponic nutrient bottle and usually they are buffered (have some acid and some base so that it absorbs some pH change).

danero2004 · Posted: Sat 30 Jul, 2011 6:24 am

Yes I agree but what about the ratio used , 6-3-6 compare to 23-6-10 both to one gallon of water

My guess is one of them must not have the correct ratio , or it is just a point of view from different sellers , or is it the ammonia inside wich added in greater ratio will affect the soil ?

Stoddo2k11 · Posted: Sat 30 Jul, 2011 6:54 am

Not really sure check the ingredients they often have lots of details including percentages, derivatives of N/P/K, types of chelates used, types of salts, etc.

I have one fertilizer that lists all the beneficial microbes. I find not substitute for reading a good label.

List it here and maybe we can figure out the chemistry.