Citrus Growers Forum

hoosierquilt · Posted: Wed 15 May, 2013 4:49 pm

Nematodes aside (that is an entirely different issue), the idea, Tropheus, is for your trees to acclimate to your native soil. If you amend a hole, then you create this small, preferable place for roots to grow, and the tree's roots may not prefer leaving that amended hole, thus creating rootbound issues down the road. Instead, it is thought that it is better to mimic Mother Nature, in placing the amendments on top of the soil, to percolate down to the feeder roots. Now, for folks with extreme soils, the concept of planting on a mound with amendments may be an exception to the rule, and I cannot address dealing with nematodes, as we don't have that issue here where I live.

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Tom · Posted: Thu 16 May, 2013 12:32 am

I must jump back in just a little. I have never heard of root bound problems in good soil surrounded by poor soil. Millett's explanation of root rot I understand but not root bound. If the roots are winding around pot when moving to in ground you have to correct that by straightening or cutting or ripping apart.

A friend in citrus in central Florida had a friend there that got into the blueberry business pretty early. Very early in the blueberry farm days they hit one year when no one else had any blueberries in the United States. Huge profit that year. Many people wanted to jump on the band wagon. My friend and others were doing anything they could to add organic matter to the poor sandy soil where the water runs right through to try to get the blue berries off and running. Blueberries do very well in low pH soil but they need some thing to slow down the water a little bit. They certainly were not putting organic matter everywhere in the field. They were just trying to help get the plants started with pine bark and leaves under the row.

I don't know if they ever hit the market as perfect again and I don't know how the efforts to plant right on top of leaves buried under the row turned out. I think on a small scale it makes sense to help out with organic matter in the hole that is twice as big as needed when the sand is what we call walking stick sand but I maybe completely wrong. I totally agree with Millet about the root rot problem but I am not yet buying into the root bound idea in good soil. Bath tub where the water stays around the roots will cause root rot for sure but I think in sand soil there would not be a bath tub effect. Tom

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skinn30a · Posted: Thu 16 May, 2013 1:20 am

I'm located 200yds off of the beach and my soil isn't soil...it's straight white sand...quartz sugar sand. Seriously, during the civil war folks would rip people off by bagging it up and selling it for sugar.

I made the mistake of amending my soil with organic matter when I planted my first couple of trees. Come to find out that it just acted as a sponge for salt. All of those trees are dead. Mother nature had it right, the sand allowed the salt to leach right through...my "improvement" was an expensive mistake.

My experience is that it's best just to sink them into the ground without amendment and mange the native soil's deficiencies with your feeding and watering program...you'll have to at some point anyway once the trees root system outgrows the artificial environment you've created by adding stuff.

Best,

Skinn30a

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Tropheus76 · Posted: Thu 16 May, 2013 9:59 am

Wow Skinn, thats interesting, never would have thought about that and would have done the same thing you did. Thankfully in my area we are a good 30 miles from the nearest salt water. My natural soil is a greyish sandy dirt that seperates once its loosened a bit into the quivalent of grey beach sand. If I go slightly deeper I start to find shells mixed in as well. Water table is fairly high too, havent dug it myself but my irrigation well(note different from drinking well at 115ft) is I am told only 10 feet or so with the table higher than that even.

I experimented last night on a bigger tree that needed to be watered. It has a 36" diameter water bowl. I turned the hose on full. Took ten minutes to fill completely to around 4" and was empty in less than one. This is an amended hole as well.

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BobsCitrus · Posted: Sun 02 Jun, 2013 4:25 pm

Out here in the rocky, arid Southwest a small, amended planting hole is referred to as a "pot in the ground" where the roots stay in the amended matter and do not venture into the less inviting, unloosened native soil. It definitely happens out here - I've seen it and done it Embarassed

We go 2-3x the width of the container, and only as deep as rootball.

Amounts and types of amendments can be debated, but the growing consensus across the U.S. is "less is better, none is optimal if your soil/drainage is at all workable".

Further: http://cals.arizona.edu/pubs/crops/az1359/az13592h.pdf : "...More than 30 studies conducted on a wide variety of soil types found that in most cases organic amendments in the backfill reduced root and shoot growth..."

105 DF here today, glad my planting is over until fall...

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Fascist Nation · Posted: Sat 08 Jun, 2013 5:47 pm

Tropheus76 wrote:

Out of curiosity, if you live somewhere extremely sandy how would not amending soil help? Water and nutrients flow through it like a sieve ....

Current thinking on a hole that does not hold water (drains in under 45 min. is my definition; though I fret over under 2 hours draining) is to amend the soil that comes out with 50% finished compost to increase the water holding capacity in the immediate area of the hole by effectively adding humus. Heavy mulching with wood chips out to a wide radius will build up subsurface humus over time. In the immediate time of 1-2 years the roots should do well and get established if you have dug your planting hole wide enough. You have to give water enough time to completely soak into the humus in the soil but not so much time that the roots are deprived of oxygen and die (and sets up a rotting condition). Fortunately trees can survive for quite a while absorbing oxygen from water so you have a lot of time in poor draining holes. Rapidly draining however must be dealt with or the tree will die of thirst or be a slow grower.

Current thinking for any fruit tree planting is a hole 1 foot deep (as deep as the was planted in the container) in a hole 4 feet in diameter. This ensures the dirt has been broken up so the roots will be able to penetrate it easier and there is more air present. This makes for a rapid growth into the hole its first year. Some advocate digging down to two feet around a 1 foot pedestal where the tree sits to increase this friable root zone. The compacted pedestal prevents the tree from sinking over time. I have noticed in nature trees live longer with a bit of a conical build up tapering away from their trunk--shedding water directly away from the tree so I try to plant mine a couple of inches above the hole. If you have a loose loamy soil that roots can readily penetrate then I doubt such elaborate digging is needed.

Similarly, arguments on how to eliminate air pockets as to whether soil should be tamped down, the tree shaken up and down while applying water or water already placed in the hole before adding soil making a mud soup before tree placement. The argument against the tamping is that you have just taken great pains to make your soil less compact, why compact it by stepping upon or tamping it down? This seems like a good argument but trees still seem to root in tamped holes.

I like to pre-dig the hole the prior day and fill twice with water, observing how long it takes to drain the second fill. (45 min or less is a real problem and needs to be explained, under 2 hours concerns me, 2-24 hours is fine, up to 48 hours is worrying and needs to be explained, over 48 hours is raised bed.) This presoaks the area as well. Explained means observation before a proposed solution. I have two small areas of my property that had drainage of around 1h15m each. In one case, it was due to the accumulation of broken down granite accumulating over years of flood irrigation coming onto the property. I dug deeper and replaced with a nearby soil and 50% finished compost mixed with a modest amount of soil sulfur to lower the pH from a know deficiency. The other hole had no such accumulation but was markedly sandy and had gopher holes. Dug out a bit deeper replaced with a mix of this soil and 33% finished compost and hoped the gophers would take care. I have no holes that take more than 4.5h to drain, but in my area ones that exceed 24 hours are likely either a clay layer is present preventing water from passing or a calcium salt layer called caliche that frequently builds up in the southwestern soils. Treatment is the same, dig down and remove or dig a hole down nearby down 4 feet to punch through and allow a drainage of this water buildup.

Soil amendments are usually not needed nor advised unless the soil has known deficiencies, such as drainage issues noted by the OP. When they are added, thorough mixing before putting soil back in hole is preferred unless the product will decomp in which case follow mfg. recommendations (which is always good advice anyway).

Container soil is greatly different from the hole the tree will find itself planted and should be washed off the roots before planting. Leaving the container soil on allows the water to shoot on past the tree in the ground and not soak into the areas immediately adjacent to the tree the the roots will grow into. I usually soak the container in a large garbage can and then hose off the roots...for larger containers an in place potting soil removal works and the tree is much lighter afterwards. This allows good inspection of the roots for problems and spreading root bound roots out rather than having to cut them off. Best to manipulate roots in the cooler early morning in the shade as roots have no protection from direct sun. Don't let them dry out which is why I like to have a garbage can with water present. Claims that fruit tree roots are overly sensitive to manipulation are without scientific merit (though I have as yet been unable to test this with fig trees since they come in a sponge like planting matrix to prevent dessication and are claimed sensitive to manipulation). Keep them wet, shaded and cool and you can work at a reasonable pace getting them into the ground in the manner you wish.

Lastly I like to scuff the sides of the hole with my shovel before adding the soil back to give the growing roots a place to dig in and exit the hole rather than circling around.

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Fascist Nation · Posted: Sat 08 Jun, 2013 6:10 pm

As for nematodes, the only solutions I am aware of is resistant rootstocks and adding predator nematodes. [Steinernema feltiae]

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Millet · Posted: Sun 09 Jun, 2013 1:49 am

hoosierquilt's, explanation of why it is not a good practice to amend the hole that a tree is going to be planted in, is generally accpeted as the correct advice, and is followed by the commerical citrus industry, and most horticulturist. Her explanation is also the same as recommended by UCR, the Citrus Department at Florida Southern College and the University of Florida. - Millet