Hello all,

I have 2 small Navel Orange Trees. Have had them for about 8 months, they dont seem to have grown at all. Should I be worried?

I repotted them into my CHC mix (4CHC's to 1 Peat Moss) but worried that the CHC chunks are too big and there is too much air in the container? Is this possible?

Or used a sealed pot and then you can bore a big hole on the side that you can plug off every time you water, and after 15 minutes take out the plug. Make sure the plug is tied to the container so that you don't misplace it.

The porosity of a CHC medium depends on the ingredients used in the blend. Coconut Husk Chips are manufactured in three sizes, 1/4, 1/2 and 1-inch size chips. The larger the chip size used the greater the porosity of the medium. I have used blends of 1-inch and 1/2-inch chips, and also 1-inch chips blended with 1/4-inch plus the peat moss additive. After 4 or 5 years experience with CHC I don't think it matters much what mixture you use, as long as you don't add so much filler that the medium looses it porosity. Of course the more porous a medium is, whether CHC is used or not, the faster the irrigation water will pass through the mix. To regulate the water pass through is the very reason for adding peat moss. I believe citrus would do just fine in 100 percent 1-inch CHC chips, with the proper watering technique to go along with such an open growth medium. - Millet

Given it time to absorb the water and dissolved fertilizer is all you need for CHC's to work properly. While coconut fiber can absorb water 6 times their weight, it still takes time for absorption to happen. And we know that water that simply drops off through the medium (exaggeration here, but what I meant almost freely draining without retention time) are never absorbed to the point of maximum carrying capacity of the potting media.

Thanks for your replies, so if the CHC's are not the problem, what can be the problem with the nil growth? I tried giving it a bit of tomato fert the other day to give it a little kick, I dont really give the small tree's any fert, want it to develop a good root system, is this advisable?

Citrus are rather big feeders, therefore require a lot of nutrition. Nitrogen is the main element responsible for the tree's growth. In fact citrus utilizes five times more nitrogen than phosphorous and almost 2 times more nitrogen than potassium. You should be fertilizing your tree a MINIMUM of once a month. A tomato fertilizer normally is a low nitrogen, high phosphorus formulation, which is exactly the opposite of a citrus tree's needs. Citrus always absorbs nutrients in the ratio of 5-1-3, which means for every 5 parts of nitrogen, a tree will absorb 1 part phosphorus and 3 parts potassium. It is not a matter of developing the tree's root system first, and the foliage second. Citrus trees rotate growth in the following order. Foliage growth, than root growth, then foliage growth, followed by additional root growth. This rotation occurs normally three times each year. You need to feed your tree with a fertilizer formula that has a higher nitrogen level at LEAST once a month if you want the tree to grow. Constant feeding with every watering by using a slow release fertilizer like Osmocote is also a good option. Little fertilizing = little growth. - Millet

Very good info, thanks Millet.

Normally, I give a 20-19-19 fertilizer to my citrus trees once a month.Few days ago, I was recommended to give a fertilizer which is rich in phosphorus, a 13-40-13 formula to support blooming.

I was planning to give standart 20-19-19 at the first day of each month and this new fertilizer at 15th, a 2 weeks rotate.

Now, after I read your message, I am not sure if 13-40-13 is a good choice for my citrus trees.But, since I give my standart fertilizer regularly, I think it will not hurt to support it with some phosphorus, what do you think?

Excessive application of Phosphorous can severely affect the quality of fruits, like thicker rinds but depends on cultivars. The phosphorous encouraging blooming are good for temperate crops like pomes and stones. But tropicals and subtropicals like citruses, avocadoes, bananas, K is much more important than P.

I would just use ammonium sulfate from now on as most phosphorous types doesn't leach out easily, and then supplement with STEM.

You can dissolve 1 tsp ammonium sulfate and 1/4 tsp magnesium sulfate per gallon of water and use that to water every time. You would still need some sources of K (which is essential for fruit production rather than P) something that I can't easily find in stores.

I've hunted high and low for STEM, no joy!!

Thanks JoeReal,

I also use Ammonium Sulfate regularly.I dissolve Ammonium Sulfate in water just as you described and pour it in the container mix.But never tried magnesium sulfate before, I will check it with my supplier.

I spray the 20-19-19 fertilizer to leaves instead of pouring in the pot mix.

So, it is better I refund the 13-40-13, I would keep it for my tomatoes but it is too much, a 5kg pack.

Thanks,

Epsom salt is magnesium sulfate, so you can get them from Longs drugs or Rite Aide or even Safeway on the cheap. In nursery shops, the epsom salts are labeled as MgSO4 or Magnesium sulfate and they are sold twice more expensive than the grocery stores, go figure!!! This is America. It is the same with many products. Buy beads for fishing from a fishing store, you pay like $2 for 10 beads. Go to Michael's craft store, the same beads would sell $2 for 200 or more pcs in a pack!

Some literature suggests to supplement 1 part magnesium hydrate for every 4 parts nitrogen, to make your citrus trees really green. In fact you use a little bit more magnesium if your plants are in the shade to build more chlorophyll for efficient capture in low light conditions. First hand experience with bananas, citruses and avocadoes.

I would certainly not use a 3-40-13 on a containerized citrus tree. Who ever gave you that advice must not know anything about citrus trees. If it was my tree I would not use a 20-19-19 formulation either. Ammonium Sulfate I believe is a good fertilizer this time of year for an in ground tree, but I would not use it constantly for a container tree. However, I understand Joe Real's thinking in your particular situation, and that is, your container's medium is already way over loaded with phosphorus (P) from using a tomato fertilizer. The phosphorous is going to stay in your container for some time , because phosphorous does not leach out. Actually the nutrition in your container is way out of balance. The latest research, disproves the old belief that high phosphorus fertilizers promote the onset of flowering in plants. Lastly, you need to flush out your container three times a year, to avoid the soluble salts build up from your fertilizers and the minerals in your irrigation water. - Millet

Thanks Millet,

Actually, I never gave phosphorus yet, ....... told me gave some tomato fertilizer, not me.

But I was recommended to give 13-40-13. Actually I asked for MAP, I've heard it helps blooming, then the seller offered me 13-40-13 if I need phosphorus, I mean it is my fault

What I give is 20-19-19 and ammonium sulfate regularly, like once a month.I hope the nutrition in my container is way out of balance yet.

If you think 20-19-19 is not the right, then I am starting to search and read the forum.

Thanks,