I put about a tablespoon in my gallon jug then fill it with water, by the time its full its all mixed which I think is better for even distribution on the plants. My trees are in 3-5 gal pots and I use anywhere from a half gallon-gallon per plant depending on the weather and how long it takes for the water to drain freely out of the bottom for about 3-5 seconds. I usually water around once a week in the spring and every 2-3 days in the summer if its really hot. I check the dampness of the soil by sticking my finger in a few inches into the soil, if its wet at all I wait. in the winter I am only watering about every 2-3 weeks with no FP but I do foliar feed them throughout the winter. It hasn't warmed up enough here yet to put them out side and increase the water/fert.

Sammers: For FP 1 tablespoon per gallon is a lot for every watering. 1tsp per gallon is the max recommended. They do say 2 tsp per gallon for watering once a month though.

In winter I do 1/4tsp per gallon and increase it to 1/2 tsp around March. In summer 1tsp per gallon. In some plants I do add CRF in Spring at half dose so they get extra fertilizer dosage.

The amount of water depends on the plants. Whatever it takes to evenly wet the soil throughout the pot. A good method is to water twice with a 10 min gap and let some of the water run out of the bottom. And then wait till the top inch or two is dry for the next watering.

Best is to make sure the fertilizer is mixed evenly. Sammers method works well too.

I also give my trees about 1 tbsp/gal during summer. I do make sure to flush out the roots well with the hose between watering. I probably give them that about 1x/week in addition to scratching in the Oscomote plus. Lots of us here feed more than the 1 tsp which is recommended because our trees in the gritty or 5-1-1 mixes that drain well. Let's see what others have to say. During the winter, I have used 1/4-1/2 tsp to fertilize them.

Tropic, I realize now it I wasn't super clear. I may water more than once a week but I only add the FP once a week max. I do use more than the recommended dose but my trees seem to respond much better to it. When I started out last spring I started with a tsp/gal and lackluster results after many people here saying Meyers in particular are "heavy feeders" and that they do closer to a tbsp/gal I started doing that and they were much happier. My mix is very fast draining and I am sure most of it washes away. Not so great for the pocketbook but I knew this wasn't a super cheap hobby in my part of the world.

I am not an expert in botany - and in fact, I do not have any good explanation of why 1 tsp/gallon should be the limit for Foliage Pro. At the same time, I do not know what "heavy feeders" mean in reality. I have read about it many times but without much analysis. Through few readings it seems plants that produce fruits/vegetables benefit from extra fertilizer for better production. I am guessing citrus growers have somewhat concluded that 3 times the recommended dosage (with respect to FP) is optimum. I will try that on some my plants this time and observe.

Second issue you both raise is that they are in free draining mix. I do not see what it has to do with fertilizing strength. Let me try a crude explanation of my scepticism.

If the plant is in a mix with little air then the roots are going to suffer and deteriorate making it less able to absorb water and thus nutrients. In a free draining mix, on the other hand, the roots will be healthier, lot denser and have the ability to suck more water and thus more nutrients. If it cannot get enough water then it will wilt and suffer even before it suffers from nutrient deficiency.

axier, thank you for your posts. Very informative.

Axier: Interesting and informative article you posted. So it seems from your calculations at 240ppm it will be just over 1.7dS/m. I am guessing you mean 1.7dS/m is max tolerable by citrus. So that would be max of 10ml of FP per gallon. That is 2 tsp per gallon. That is what dyna gro says you can apply if you are on a schedule of every 2-4weeks. Otherwise 1tsp per gallon every watering. It is quite likely that Dyna Gro's recommendations are safe numbers and one can go higher within reasonable bounds.

But according to your numbers applying 1 tbsp/gallon would put the plant at risk since its ability to absorb at that concentration will be impaired. Until the next watering assuming it is just plain water. Or am I missing something important?

Anyway to the OP - Atara. I guess you were expecting a simple answer and here we have digressed to nitty gritties of ppm, EC. It is interesting to me though.

A while ago - don't remember how long exactly, a few of us engaged in a healthy debate about not only citrus being heavy feeders, but lemons and limes in particular among citrus having higher N requirements. Vladimir and I found some peer-reviewed documentation that substantiated these claims (initially I heard them from JohnM regarding Meyers). I can't find the thread now, but the basic jist was that 1. Lemons and limes are more acidic than other citrus and thus need more N (don't know why this is), and 2. They grow more rapidly and produce heavily often bearing multiple fruit loads per year. I equated it to the nutritional requirements of an athlete vs those of a sedentary person - the more you burn, the more you need to eat.

" I am guessing you mean 1.7dS/m is max tolerable by citrus." (tropicofcancer)

Not, citrus can tolerate much more! 1.7 dS/m is the optimum value, it is not the maximum.

For example, taking into account that citrus produce 100 % yield with 1.7 dS/m, it would produce 80% with 3 dS/m. These data are from studies carried out in California, Israel and Australia ("Citrus Production manual" (University of California book, page 136).

So, if you fertilise with 3 dS/m in each watering, your citrus can grow well, but you will get just 80 % of relative yield that you would get with 1.7 dS/m, so you are wasting money and stressing your citrus plant.

"Atara. I guess you were expecting a simple answer and here we have digressed to nitty gritties of ppm, EC."

Probably you are right, if he wants a simple answer, follow FP instructions, your citrus will be healthy although not in its best.

But, as the proverb says, "Give a man a fish, and you feed him for a day; show him how to catch fish, and you feed him for a lifetime."... I prefer to show how to catch fish. ;-)

Tropic, I don't pretend to understand the science behind any of it and have kinda gone on trial and error and recommendations of other citrus growers on this forum. My very crude thinking on why a porous mix requires more fertilizer is that most of it ends up draining away out of the pot (within minutes) before the plant has a chance to use it, versus in a more water retentive mix where more fertilizer remains in the pot to be further utilized by the plant. I started with a tsp/gal and my trees leaves kept getting lighter and lighter, I up'd the fertilizer slowly first to 2 tsp/gall then to a tbsp/gal before I found what kept my trees leaves a steady green. It may very for others and I know I am wasting most of it but unless someone has another solution, it works for me as of now and I expect the extra cost for half the year. I am planning on switching my trees over to Jacks Professional High Performance Fertilizer, It arrived today actually (on the recommendation of others that have successfully used it) and will do the same "test" I will start off at the recommended dose and add more if the trees show a prolonged nutrient deficiency.

With a medium as open as the 5-1-1 medium, close to 96+ percent of the water applied to the tree's root system just quickly passes through and is wasted. The same goes for the fertilizer that was dissolved in it. It is known that the root system of a plant growing in a container does best when growing in a medium that has approximately a 25 percent aeration and 75 percent solids. This is the medium/air ratio that all nurseries strive for. I've never tested the 5-1-1 mixture but it has to be close to 85 percent or more air. Plants can certainly grow in the 5-1-1, but it takes a lot of extra effort, watchfulness, and an over abundance of wasted water and fertilizer. If the grower is not careful with such an open medium, the root system, goes through periods of semi-drought.

I have tested the 5-1-1 and it had an aeration porosity of 35 %, which is not much greater than the 25% which you say is optimal. How did you arrive at 85%?

Vladimir, you state that the 5-1-1 has a 35 percent aeration porosity. I have a difficult time believing that. However, like I wrote I have not tested it. With a 35% porosity, that means the 5-1-1 would then have a 65% solid base. With 65 percent of the medium solid, it seem strange that liquids would run straight through the medium with almost no resistance. I will have to take you at your word at this point. This has enticed my curiosity, so I will test the 5-1-1 and determine the porosity for myself. Fortunately, where I work we have an on site testing lab, therefore it will not be much of a problem. Take care, I'll report my findings.

How did you arrive at 85%?

Vladimir, I arrived at 85% by a very non-scientific assumption of the almost immediate liquid pass through, plus the minute amount of water and fertilizer the 5-1-1 medium retains as the liquid quickly is leached out the bottom. Anyway we'll see if I am close to right or not. I'll let you know the results of our testing lab people.

I tested it past year in "my" version of the 5-1-1 mix, and obtained porosity value closer to those of Vladimir and it doesn't leach 96 % of the water, much less! Not very different from others aerated substrates.

You can see it here:

http://forums.gardenweb.com/discussions/4007891/do-you-screen-out-fines-from-pine-bark-mulch-for-5-1-1?n=7

Since then, I have fertilised in some containers (in others used other methods for comparing) with fertilizing in each watering, with FP or other fertilizers.

In the growing season, used 150 ppm and 200 ppm N in grow flushes.

The results were excellent, I got the best plants with this method.

The advantage with FP, it includes all elements the plant needs (micronutrients included). If you use another fertilizer without micronutrients, you have to supplement it.

Sammers: I am not trying to put you down and I have no interest in
doing that. By mentioning your recommendation it raised my interest in
the the topic. Specifically, I tbsp per gallon of FP seemed excessive to me and Axier provided some very good info on that. I should really thank you for that. But I like to
question where are the basis of various recommendations. This is
where I come from: 511 and gritty mix try to address two primary
requirements - water and air (oxygen for all practical purposes). These
mixes are primarily targeted to balance these two very crucial needs.
Second to these requirements is that all the nutrients must be water
soluble. So nutrient uptake is directly related to water uptake. If the
plants wants 1 gallon of water in a day to quench its thirst then it
will suck that much up and get the nutrients it contains. If it cannot
get that then it will first suffer from water deficiency. In that case
one would have to water more frequently anyway and the plant would still get its nutrients.

Silica: So let us take 511 that is 85% bark and peat and let us also say perlite is all air. In order to get to your claim that 511 is 15% solid I will have to compress 85% of bark and peat to 15% - not happening by any means. Axier's numbers are very close to what I have measured.

Like Axier I skip the peat for most of my plants except for outdoor annuals. Much better results even though it has less water holding capacity than regular 511. For some I even screen the pine fines below 1/8 inch and add back a measured amount to make a 411 mix with even better results for some plants like ficus.

axier thank you for your excellent post. As you have already done the test there is no reason to conduct another one. As yours show a 40% porosity in one test and a 53% porosity in the other, I will take them as a good solid estimation. I appreciate your information. Still that is quite a lot higher then nursery recommendations, but with proper care it is neither here or there. Good growing to both of you.

Axier, thank you for the link. I tried reading through the article and I just don't have the patience for the science i guess. It seems from the other great posts and the article you linked, that you feed your plants the same way you water - until it starts draining out the bottom (leaching?)

The problem for me is that with ten 7 gallon pots, thats a lot of fertilizer to go through even if i follow the FP directions and go with 2 tsp per gallon - its going to be around 6-9 teaspoons per feeding!

I am currently using CRF (lutz tabs) in the pots and haven't had any deficiencies yet, but i did want to start adding FP to their diet as they are young and I want them to start fruiting. I guess I'll experiment with the FP once every other week and see how it goes.