Pine needles for mulch and compost

When I lived in Mississippi, where the soil is very acidic, there were many pine trees and people used the needles as mulch for azaleas and camellias a great deal. This was the conventional wisdom there and it did seem to help. However, in New Mexico, where we also have lots of pine trees and alkaline soil, the conventional wisdom seems to be that pine needles as mulch or in compost would be harmful. I used them anyhow on the grounds that any organic better was better than no organic matter, and my garden seems to have suffered no ill effects.
Pine needles do seem to take a while to compost or break down as mulch but other than that they seem quite a nice source for organic matter. Am I courting disaster? Is there something wrong with using pine needles that I am not aware of?
I would really appreciate hearing from some of you who know. In general the pine needles I use are the ones that fall from the trees in the fall.
Betty

I tend to agree that any organic matter is better than no organic matter.

The reason pine needles make a nice mulch is because they do take so long to break down.

The only problem I could see from using pine needles is if you were using them as mulch for something that preferred a very high pH. Other than that, I think they are fine.

Thanks joepyeweed. My suspicions confirmed.

We found the pine and fir needles to have an allelopathic effect in the garden when they were freshly dropped from the tree. I'm referring to gardening in the Tahoe Basin in the Sierras. I think it is more than the pH effect. Certain plants were fine with a pine needle mulch, but many of the ones that my mom liked to grow would struggle if we left the needles. I think this has the potential to be true of many aromatic trees, which is why very few plants tend to grow beneath a pine, cedar, eucalyptus or camphor tree. The trees are always dropping a fresh layer of needles or leaves which still contain the enough volatile oils to suppress many plants. Once these are fully composted, the problem will likely go away, althougth you may need to adjust for pH before you use it.

allelopathic - thanks for giving me an opportunity for growth! I had to look this word up, but now I get it.
I would not use fresh pine leaves on my plants. Typically I compost my pine needles which are brown when dropped, but on occasion, I use them for mulch. So far no disasters. More disasters from unmulched or uncomposted plants.
One problem with evergreens, besides the possible allelopathic effects are the lack of sunshine. I notice that the lower growing the branches the fewer plants underneath. The same is true under live oaks in Louisiana where the branches touch the ground if unpruned.
Anyhow, I take your word on not using fresh aromatic leaves on growing plants, but to compost them first. It sounds reasonable that this would be bad.

I apologize for not being clear. The "freshly dropped" pine needles I was refering to were brown, not green. They still seemed to create some problems when they were fresh fallen from the tree. Most of our evergreens were tall with no branches lower than ~25 ft from the ground. I know that some people have been able to use the brown pine needles without difficulty. It may be the variety we had in the yard, or something to do with the growing conditions. The natural soil in our yard was ground granite sand and pine needle dust. My grandmother started amending the front yard area with organic materials to grow some flowers and small lawn. My mom carried on the tradition and expanded the garden. Whenever we tried to make use of the pine needles, the plants would suffer.

Oh, now I get the message. Even the brown ones caused troubles. But I gather the troubles were immediate, not a few years later.
Betty

We raked the pine needles up and only composted a few, so I think it would be fair to say that the problems with the needles were more immediate. As I understand it, the discovery of negative effect of the pine needle mulch on the garden plant growth was an unexpected outcome of a defensible space program initiated by the local fire deparment. My mom noticed how much better the plants were doing when all the pine needles were removed.

Edited for clarity now that I'm awake.

This message was edited Sep 7, 2006 7:48 AM

I use all of the pine needles I have which is LOTS! I shred some and leave others whole in my compost pile. It adds structure for a long time to the soil and holds moisture in the compost pileand soil it is added to. I do think it adds an undesirable taste to my root crops in my veggie garden. I probably have 10 to 20 % pine needle in every compost pile I manufacture here. The soil under any pine tree is extremely dry and plants die from lack of water and suffacation of accumulated pine needles. I have raked off and ammended soil under my ponderosas and they yeild a productive site for shade tolerant plants. The over head tree will not let any water fall underneath though and you need to irrigate.

Yes, I have noticed that plants anywhere near my ponderosas have to be watered deep and often. I lost several tomato plants, I believe because the pines sucked all the moisture out of the soil. ( I was using a soaker hose then.). When I put drip irrigation on them, the tomatoes began to grow. Haven't noticed an unpleasant taste in my carrots and turnips yet, but I don't think I use as many pine needles as you do.
Betty

My yard is bordered by (other people's) large evergreens--Colorado spruce, I believe-- and a row of huge cottonwoods. If I want to make mulch, there is no choice but to use the acid needles and alkaline leaves. Haven't pH tested the results, but I figure the two have to balance each other out to some degree!

The epimediums and hellebores I planted a couple of years ago inside the drip line of a pine tree seem pretty happy. They do get runoff from rain, and I water them occasionally.

Leaves alkaline? I thought they were acid. Does it vary tree to tree or am I just mistaken?

All carbon in plant form break down into carbonic acid or some other acid and water. The soil around will neutralize the acidity. I'm sure the acidity of each plant is more or less.
The soil around my ponderosas needs clay added and lots of water holding compost. Because when needles break down they are just dry dust and no soaking will correct. That is why I combine them with the soil ammendments, Clay, Manure, and Wood chips.
Hey I was driving out in the valley watching the sunset and found a huge pile of cow manure and sawdust. I can't wait to get it home. Right now I need to work on this tomorrow. Split and stack.

Pajaritomt, the pamphlet on composting I bought along with my compost-tumbler-turned-soil-mixer warned that certain types of trees--notably cottonwoods--had very alkaline leaves and one should not compost them. Which meant that the entire contents of my yard in the fall would be unsuitable! Maybe it's time to pH test a soup of ground-up leaves and check out that piece of information.

Goldenberry,
I find it very hard to believe that any leaves are alkaline except with the possiblity of things like Salt Cedar that grow in very alkaline areas. I am virtually certain that even compost leaves will turn out to be acid when they decay. I have a whole bunch of them coming as soon as they fall in a friend's yard. That's how sure I am. Leaf mould is on of the best fertilizers there is, but it is acid.
I will check with my county agent, with whom, I plan to cultivate a relationship, now that I have met him. He seems like he knows what he is doing.

Soferdig,
Now I see how you cultivate your youthful figure! Actually, I used to be a school teacher, of teenagers no less, and during that time I split a huge amount of wood. I found it very satisfying. Hope you enjoy yours. Or do you have one of those fancy hydraulic woodsplitters. Such a gadget would probably be worthwhile where you live.
We have a huge amount of wood left over from Y2K and probably won't need any until about the year 2020 by which time it will have been turned to sawdust by insects. We don't set fires in our fireplace very often. The house is well insulated and whenever we build a fire we endup overheating the whole place. But when there is a power failure, it comes in handy. Luckily we haven't had any long power failures.
I have a huge number of trees that need to be cut and split in Mississippi, but, I don't see myself getting to it. The neighbors will probably get them which is fine with me.

Every night my DW and I sit by our enclosed glass front fire and read, sleep, watch TV, or just sit and watch the flames dance to the sounds of nature being released by the combustion of wood. We go thru over 8 cords every year. Yes I like to keep active and build callouses. It keep my diabetes in control. We go up in the mountains and pick up logs left behind after logging and bring them home and I cut them up and split them with a hydrolic splitter. Too much wood to split like Abe did. I especially love Larch to burn it is beautiful and very warm. We heat with gas forced air but it never comes on until 4 or 5 am and only burns a little when we are gone.
This is how I keep my youthful figure. This is fun work. Racing Sailboats.

There is nothing more beautiful than a sailboat flying its spinnaker. You picture is lovely. I envy your opportunity to sail.
Katrina left me a lot of down wood in Mississippi, but I am terrified of chain saws and don't have a splitter so I let the neighbors cut it up and use it. Only one problem, they have plenty of wood from their own down trees right now. But we will clear it up eventually. I bought a small chain saw and am promising to get over my fear of it this fall when I go to the farm. I also have some large pieces of oak that have been lying around forever in my barn. I will be burning them for a while.
I want one of those outdoor fireplaces so I could sit out by the lake and have a fire there. I like that better than the fireplace in the house in Mississippi.

you need to go to the library and get a book on how to safely use a chain saw. I have studied one called "Barnacle Parps Chain saw guide" It lets me understand what to do if and how not to get in trouble.

Good idea. I certainly need to use that chainsaw and learn to do so safely. Right now I have just looked at it.