I started with Citrus in containers last year and while my trees have done OK, I wanted to get a better grasp on what their requirements really were. I understood that they don't like wet feet and appreciate a fast draining planting medium. What troubled me was that I couldn't find out any good information on what they require for optimal nutrition. There are a lot of products on the market labeled 'citrus fertilizer', but I have found them to be silly. One product is high in nitrogen, another high in phosphorus etc. How can the ratio of nutrients be so different if the makers of these products understand the requirements of citrus?
So, I started researching.
What I found really surprised me and it may you.
Many of you may believe citrus are heavy nitrogen users. Some of you might think a high phosphorus fertilizer will promote more blooms and thus fruits. Turns out you would all be wrong ;)
As it turns out the nutrient citrus use more of than any other is a nutrient that many fertilizer products have little to none of... calcium.
I don't expect anyone to take my word for it so here is a link to the U of Florida's finding on citrus nutritional requirements. http://edis.ifas.ufl.edu/CH046
The table showing the ratio of each nutrient citrus use is at the bottom.
While I have understood for a few years that the amount of calcium plants require for optimal development is often not reflected in commercial fertilizers, this would be the first time I have encountered a plant whose calcium requirements were roughly equal to the amount of nitrogen, phosphorus and potassium combined.
thoughts?
Nutritional requirements of citrus in containers
Can you use egg shells for calcium
what types of citrus have you put in containers? and are they producing fruit consistantly?
Egg shells can be used for calcium, but it takes a long time (a year or more) before it will add any usable calcium to the soil.
As for types of citrus I have in containers and whether they are fruiting constantly: I am new to citrus (last year) so there is no constant fruiting of anything. I have lemon and kumquat currently with a couple orange trees on order.
As I have learned more about this I would not say it is essential to add tons of calcium to the container mix or fertilizer, but that it is apparent calcium is being used by tree in significant amounts. Many fertilizer products lack calcium entirely.
Lime in the mix can take care of adding calcium, but if the fertilizer doesn't have any calcium, the lime in the mix decreases over the season. Just something I think about and thought some of you might think about as well. Particularly for those who don't repot their trees every year (who does) adding calcium may become more important as the lime value in the second year will be much reduced.
As an FYI, I contacted a U of Florida Citrus Research and Education Center person and he indicated that for container/hydroponic citrus he uses equal amounts of calcium (calcium nitrate) and nitrogen even though the water supply there contains 60ppm calcium.
His response only discussed ground grown vs hydro grown (container growing is much closer to hydro than ground growing), but I did ask him a follow up pertaining strictly to container culture(as container mixes are often limed which supplies Ca) and will update if/when I get a reply.
Informative post, thanks for sharing
I have a lemon tree in a five gallon bucket - any thoughts on how much lime you would need to add?
how much lime to add depends on the acidity of the mix. A peat or bark based mix would be very acidic and would get around 1/2 cup of dolomitic lime per cubic foot (a cubic foot=7.5 gallons).
This normalizes the pH and supplies calcium. A coco coir based mix or any non acidic mix wouldn't get limed, but gypsum might be used at the same amount as lime.
A fertilizer containing calcium is probably a good idea. Very few have any, but ferts like DynaGro Foliage Pro do.
I just have it planted in Miracle Gro potting soil
That mix comes pre-limed. If you wanted to increase the calcium you could use a fertilizer with calcium such as Foliage Pro 9-3-6 or you could add gypsum by scratching it into the first few inches of mix.
is there a special blend of soil that is best for growing container BANANAS???