Went to Home Depot yesterday, was surprised to see that a 50-lb Bandini 21-7-14 all season lawn fertilizer is on sale for $10! That's $0.20 a lb! The regular price is $16. Anyway, if you have citruses inground and are maintaining them for fruit production instead of growth, this is one of the cheapest near-perfect fertilizer that you can use on your citruses and avocadoes.

Although commercial growers will usually obtain fertilizers far cheaper than us hobbyists do. When I used to do rice research in my graduate studies, we obtain them in Bulk from ag supply stores and they are about 5 cents a pound!

Hi Joe,

You mentioned that the Bandini fertilizer is nearly perfect for inground citrus maintained for fruit production. What fertilizing regimen would you recommend for newly planted trees maintained for growth? I could use a suggestion for both inground and container trees.

Thanks,
Eric

Buy the more expensive one, like Vigoro's Citrus and avocado fertilizer formulation. Apply one dosage as per instruction now, and then a month later, apply ammonium sulfate every 2 weeks (divide monthly dosage into two) until end of July, the rate would depend on how large is your tree. You can dissolve ammonium sulfate in water using a bucket and use that to water your citrus. There is a recommended water to fertilizer ratio when dissolving ammonium sulfate so that it will not burn your roots. You can search it here, just can't recall directly from memory. This regimen provides the minors from Vigoro fertilizer and the nitrogen provides for aggressive vegetative growth, assuming you plant inground in California.

Ericbeeghly, you say your tree is newly planted, therefor I guess the tree must be approximately 1 or 2 years old. Fertilizing a young citrus tree of this age the usual formulations recommended to use, are either a 6-6-6 or a 8-8-8. For young trees only lower analysis fertilizers should be used during this time to avoid damaging the young citrus roots with fertilizer burn. Apply fertilizer uniformly in a 3 foot diameter circle around the tree. As the tree becomes older, the area fertilized should be enlarged as the root system expands. Do not apply fertilizer directly against the trunk. For the formulation 6-6-6 apply 3 to 5 pounds of fertilizer per tree per year, divided into 5 applications (.6 to 1 pound/application). For a formulation of 8-8-8 apply 1.8 to 3.8 pounds of fertilizer per tree per year divided into 5 applications (.36 to .76 pounds/application). This give the tree the recommended amount of ACTUAL elemental nitrogen required by new citrus trees which is 0.15 - 0.30 actual N. Reference "Your Dooryard Citrus Guide."

Millet

Millet's recommendation is good. Further, for young trees, it is best to dissolve the fertilizers and then apply them around your tree. This method is the most forgiving to common beginner's mistakes of over application. Applying fertilizer in powder form into the root system directly should best be done if you know exactly what you are doing, such as well-seasoned citrus growers. So for a first timer, if you can dissolve those fertilizers, it is recommended to do it. The rest of the undissolved stuff that remains, you can incorporate them around the tree line as this will not hurt the trees either, the fact that they are not easily soluble.

Thanks for the info! Is it important that the N-P-K ratio is 1:1:1? I've read throughout the forum that the magic ratio is 5-1-3. I have quite a few plants, and I would like to experiment with all methods, including organic. Alfalfa pellets have a formulation of 5-1-2 while containing micronutrients and triacontanol, a fatty alcohola of the general formula C30H62O, also known as Melissyl alcohol or Myricyl alcohol. Triacontanol is known to be a growth stimulant:

ALFALFA EXTRACT BOOSTS CROP YIELDS, Michigan State University horticulturist Stanley K. Ries reports that a plant growth stimulator originally extracted from alfalfa (but present naturally in most plant foods) is capable of boosting the yield of asparagus, sweet corn, cucumbers, carrots, radishes, tomatoes, and navy beans by 7% to 22%. The substance-triacontanol-is active in exceedingly small amounts (one pound of triacontanol is enough to treat about 900,000 acres of crops) and appears to enhance the growth of plants without increasing their consumption of nitrogen fertilizer.
(Here's a detailed study: http://www.plantphysiol.org/cgi/reprint/68/6/1279.pdf)

and even thought to boost the brix levels of citrus:
http://flcitrus.ifas.ufl.edu/UF%20IFAS%20Short%20Course%20Proceedings/Fresh%20Citrus%20Quality/methodshigh.pdf

I was thinking of adding a bit more potasium by adding some comfrey mulch or tea. I also plan on using foliar feeding until the weather warms up. Lance Walheim seemed to think that organic foliar sprays might not work. He told me that urea applications were best. I plan on applying fish emulsion.

Any thoughts? That study on brix levels of citrus was done back in 1987. Have there been any new findings?

Thanks,
Eric

The 1-1-1 ratio Millet was talking about is for young trees planted ingorund. The 5-1-3 ratio is for container plants and is the ratio that citrus trees actually use, so applying the exact ratio in containers helps prevent salt buildup. The use of 1-1-1 for inground trees is due to the fact that nutrients in soil are continuously leached or irreversibly bound to soil at varying rates.

As for organic forms of nutrients, aside from the fact that they may contain trace elements and are released more slowly, it really doesn't matter to plants--they are often very specific in the actual form of the element that can be take up and that is the form that most commercial fertilizers supply.

Organic fertilizers do change the nature of the soil, creating a more organic soil, but I am not sure if that is better for citrus-- maybe some of the real experts can comment on that.

Eric, if you use the 21-7-14 fertilizer, that would make it a heavier ratio towards the K side, which should sweeten the citruses according to the discussion logic. Of course I would have to test it myself in this unreplicated piece of land,

Ericbeeghly, growing citrus organically is more or less commonly done, of course, to a lesser extent then standard (Chemical) methods. The biggest problem with organic culture is providing the tree with enough WATER SOLUBLE potassium. Citrus can ONLY use nutrients when they are in the water soluble form. When organic fertilizers are applied they must first be "broken down" by soil bacteria before they become assessable to the tree. Citrus are heavy feeders, therefore require a larger then usual amount of nutrients then most plants. Over many years evidence as shown that organic culture does not produced the quantity nor quality of production as standard citrus culture. I have nothing against either organic culture or chemical culture. On our farm we use both systems. For fertilizing, we rely on chemical fertilizers, however, we also recognize the value of organic incorporation, and grow cover crops (mainly rye, and clovers) to be turned under as an organic green manure. Take care and good luck with your tree. - Millet

In addition to what Millet said, plants can also take fertilizers directly through interception, that is the roots will get into physical contact where the insoluble fertilizers are located by simply growing into them, and then with proper root exudates to alter the pH around the roothairs, or mycorrhizal relationship, those previously unavailable insoluble forms will now become available to the plants, and can be taken in through active uptake, passive diffussion across concentration gradients, or mass flow when these are dissolved, which in support to Millet, they will be ultimately taken up when these nutrients travel with or through the water along the transpirational stream for delivery to various plant parts.

The large national chain super markets in Denver, market both standard grown citrus and organic grown citrus. The organic oranges are smaller in size, with a higher degree of peel blemishes, and always more expensive. - Millet