proper proportions for peat moss (tree planting)

gw409(6)May 12, 2012


i have been planting a lot of large green giant arborvitaes

5-7 ft. i dig a large enough hole to accommodate the root ball and back fill with a mix of about 25% peat moss and original soil. after the hole is filled i make a small trench around the perimeter of the root ball an put about one cup of bonemeal and cover it up.

i am never quite sure about the optimum proportion of peat moss? is my method ok or is there anything else i can do to give the tree the best possible start?

thank you

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I'm not sure why anyone even bothers with peat moss. If you don't have your own source of finished compost, track one down.

Aborvitae are hardy. In my Georgia red clay I have dozens of them thriving. I did nothing more than dig a hole a few times larger than the container and mulched after planting.

    Bookmark   May 12, 2012 at 1:15PM
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rhizo_1 (North AL) zone 7

gw, it is no longer recommended that the planting hole be amended with peat moss, compost, potting soil, ANYthing. Doing so creates an environment that the roots of the newly planted tree or shrub may never leave! Such a practice can also cause something of a bathtub effect as irrigation or rain water cannot evacuate quickly.

I know that it goes against the grain, but studies have shown that roots establish themselves MUCH faster into the surrounding soil when plants are installed in unamended planting holes with natural backfill.

The hole should be dug no deeper than is needed for your plant to sit AT or just ABOVE natural grade....but quite a bit wider. We like to suggest that a planting hole be shaped like a basin.

After planting, a two to three inch layer of mulch can be applied around the area, but never piled up against the trunk. I'd not use bone meal when planting. It does not provide a benefit and may cause harm. As a matter of fact, newly planted woody plants should not be fertilized with anything.

The exception to the 'no amendments' rule is if you are preparing an entire bed for planting. In that case, adding improvements in the form of organic matter is terrific.

Here is a link that might be useful: Information about bone meal

    Bookmark   May 12, 2012 at 2:22PM
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The proper proportion of peat moss is ZERO. Just backfill with the soil you removed from the hole.

If you want to give the tree a great start, dig the hole the depth of the rootball and several times as wide as the rootball (wide and shallow). Break up any clods in the dirt you have removed.

Fill the hole with water and let it drain to put a supply of water under the roots. Then set your plant, backfill with the original dirt, GENTLY pat the dirt around the rootball (use your hands, don't stomp on it) and thoroughly water, then mulch the entire area you dug out.

The moist loosened dirt will make it easy for the rootball to send new roots out into new dirt, and the mulch will retain soil moisture.

Check soil moisture with a moisture meter and water the new plants thoroughly when it's starting to dry out a few inches below the surface.

    Bookmark   May 12, 2012 at 3:00PM
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Whether the planting hole for a tree or shrub should or should not be amended depends on the soil you have. if you soil is clay then amending that planting hole with organic matte of any kind can create what is called the bahtub affect where the soil now holds too much water and drowns this newly planted tree or shrub. However, not amending the planting hole in well drained sandy soils can result in this newly planted tree or shrub not getting enough moisture to survive.
So, do not amend the planting hole in clay soils but do amend the planting hole in well drained sandy soils.

    Bookmark   May 13, 2012 at 7:09AM
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No, do NOT amend the soil in individual planting holes regardless if it is clay OR sand!! If your soil is very sandy, you may need to amend but you should do so over the widest possible area you can manage - ideally the full mature root spread of the tree. If you can't manage that, then just apply your amendment as a topdressing or mulch - it will provide the same benefit without compromising drainage or altering the soil interface.

Amending individual planting holes regardless of soil composition is completely outdated and no longer a recommended procedure. Water is really the ONLY amendment or additive a newly planted tree or shrub needs - no fertilizers or vitamin root stimulants either.

    Bookmark   May 13, 2012 at 4:10PM
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I guess I goofed then. I transplanted over one hundred Eastern White Cedars by digging a hole, adding peat moss to the soil I dug out, some fertilizer and water. Two trees died, one got run over by a discer (I swear it jumped in front of me) and the other got broken to bits in the winter when a snow fence broke during a blizzard and pummelled it to death. These trees were 2-3 feet tall at transplant and were yanked out of a sand pit bare root. Some are over twenty feet tall now.


    Bookmark   May 13, 2012 at 7:48PM
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blazeaglory(10 SZ22/24 OC Ca)

A tree will still grow in an amended hole but studies have shown (so Ive heard) that a tree will grow quicker and send more roots out of a non amended hole. I have sandy loam soil with alot of organic matter. It drains good so every time I plant something I back-fill with the original soil. But when I first started growing I thought It was fun to go buy a bag of MG soil and mix that in the hole and with the soil. All my plants and trees are growing fine now and the ones with natural soil are no different than the ones with MG soil(not that it is much of a soil). Anyways, I think one of the proper methods is to back-fill with original soil (clay soil could use some amending ahead of time), and top dress in a lasagna style method with compost and manure and maybe some granule fertilizer. Its up to you what you want to use but I think top mulch with at least compost and manure.

When I first started growing I planted 3 hibiscus bushes. I patted them down and then walked in a circle to compress the dirt right around the crown/trunk. Im 210 pounds and I really put my weight into it. Now the soil is pretty hard but still able to dig through with some effort using my fingers. The bushes are growing fine but I dont recommend using my "stomping" method. Like rhizo said just press

    Bookmark   May 13, 2012 at 8:41PM
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Because sandy soils do not do a very good job of holding onto moisture, except if there is a barrier such as hard pan to keep that water from draining out, anything planted in unamended sand will never have enough soil moisture available to grow. Even covering that sandy soil with a heavy mulch will not be enough to provide those plants with adequate amounts of moisture to promote strong and healthy growth.
If the gardener can amend a very large area of sandy soil that should be done, as it should also be done with clay soils. Organic matter in any soil is good, and most all soils I have seen over the years all need more organic matter.

    Bookmark   May 14, 2012 at 7:05AM
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Tiffany, purpleinopp GardenWeb, Z8b Opp, AL(8B AL)

Hi & welcome to gardenweb. As you can see, you kind of hit a "hot spot" asking about peat. Don't take it personally & good luck with your shrubs! Hope it's good to know you can spend that peat money on something else.

    Bookmark   May 14, 2012 at 9:58AM
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"These trees were 2-3 feet tall at transplant and were yanked out of a sand pit bare root. Some are over twenty feet tall now."

Sounds like whatever you did worked!!

    Bookmark   May 14, 2012 at 3:36PM
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Hey Zeus,

It's a frickin weed, for heaven's sakes, I grow weeds occasionally, as well. I took some kudzu sitting outside in a pot all year, I planted it too deep and it has grown into a twenty foot circle this spring. I took a rootbound paulownia, shoved it into a decrepit garden bed, and it grew twenty foot last year. I planted a bamboo from the mountains, it spread twenty foot in two years, I tossed it out due to chlorosis. And anybody that plants one hundred of them thangs ain't got no taste in the first place, unless they was gettin' paid fer it...then, should have told the owner no ...cheeze....


    Bookmark   May 14, 2012 at 4:35PM
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Love this thread.

Chorus: "You can't do that."
Gardener 1: "Hmmm,I did that and it worked."
Gardener 2: "I could have done that, anyone could have done that. I've done similar things. It was stupid of you to do that. You shouldn't have done that."

    Bookmark   May 14, 2012 at 5:43PM
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blazeaglory(10 SZ22/24 OC Ca)

toxic. You just described every forum on the

    Bookmark   May 15, 2012 at 2:11AM
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darth_weeder(z7 NY)

Lloyd it appears that the cedar that committed suicide in front of your discer was just trying to get away from the peat you placed it in. just a hunch.

    Bookmark   May 15, 2012 at 12:10PM
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No one said you CAN'T amend with peat moss or anything else - only that it is no longer advised for a number of very good reasons. Like anything else based primarily on science, horticulture or the growing of plants is highly influenced by continued study, new discoveries and ongoing scientific testing. Sure, countless plants over the years have been planted into highly amended soil and they have survived. But current evidence supports the contention that utilizing approved planting methods into native or unamended soil will encourage faster establishment and better long term results.

And since it has proven to be not necessary to amend, costs money to purchase soil amendments and involves a bunch of extra work, why not follow the advice of the pros and skip it??

Here is a link that might be useful: the myth of amended soil

    Bookmark   May 15, 2012 at 2:16PM
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Thanks for the link gardengal. I was just having a little fun, not necessarily arguing the point.

The one-pager did not have enough detail for me though. I assume there were studies growing a statistically significant number of trees side by side in amended and unamended holes? I don't know how you'd actually measure root growth of a several years old tree, but then I'm not a horticulturalist.

    Bookmark   May 15, 2012 at 4:32PM
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