Alfalfa as Mulch
Question from Robin:
Thank you so much for the informative and entertaining lecture last night! It was a pleasure to meet you finally in person – I gave you my card – Harmony Organic Gardens. and said that I would send you information about the compost/amendment source I had asked you about – I don’t know if you’ve had any experience with them, but my soil science instructor at Mira Costa College – Meghan Farleigh – really likes Mary Matava’s products, so I am going to try some soon. Here is the link:
http://www.agriserviceinc.com/index.html
Meghan also swears by alfalfa for mulch and I think I heard you say you didn’t recommend this. Can you explain?
Answer from Pat:
Robin: Thank you for attending and enjoying the talk and for the information on top soil. People often ask for good sources. I am intrigued in what you told me about using alfalfa for mulch and want to hear more about it. First to define the term “mulch”: Mulch is an organic or inorganic material placed on top of the ground to help maintain moisture in the ground and cut down on weeds. Organic mulches gradually break down and eventually when thoroughly rotted improve the soil. Inorganic mulches such as black or red plastic can be used to heat up the soil and the air in cool coastal climates and increase yields of certain crops such as melons. Organic soil amendments and aged compost are different. These are well-enough rotted to be combined with the soil without subtracting nitrogen from the soil in order to rot. Alfalfa is in this category since it is a legume and thus has a high nitrogen content. For example, alfalfa can be grown from seeds planted in spring as a warm-season cover crop and dug directly into the ground in fall to improve the soil.
Because of its high nitrogen content I am sure that alfalfa used as mulch would quickly break down and then could be incorporated into garden soil, but some might dry out on top of the ground thus allowing some of the valuable nitrogen contained in it to escape into the air. (This can happen with any fertilizer left on top of the ground and not watered or cultivated into the ground.) Baled alfalfa seems like an expensive material for mulch when much cheaper or even free organic materials make excellent mulch. Baled alfalfa is a commonly used food for horses and other domestic hoofed animals. Moldy alfalfa hay, however, would make horses sick if fed to them, so it can often be obtained free if one can find a source. Ground alfalfa meal or alfalfa pellets are used as rabbit food and also as an organic nitrogen fertilizer which one can work directly into the soil. (For more details, see my book and the chart on generic fertilizers on this website.)
Another reason one would not normally think of alfalfa as a mulch is because it is a legume. Leguminous plant materials, such as bean straw and green alfalfa, can be dug straight into the ground since they contain enough nitrogen to rot quickly in the ground. Alternatively one can layer alfalfa with a manure, such as clean horse manure as I suggested last night to make a very nutritious compost and do so amazingly quickly, within a month or two, without tossing and turning. (See the detailed explanation on pages 35 and 36 of my organic book.) Another reason that I would be a little hesitant to use alfalfa hay as mulch is that alfalfa left lying on top of the ground near stables, for example, has the tendency to attract rats, opossums, racoons, very hungry coyotes, rabbits, and other animals who like to eat it. (Dogs and cats, however, can keep pest animals away.)
I would like to know more about why Meghan likes using alfalfa as mulch and what her experiences are. Perhaps there are no animal pests where she gardens or perhaps there are other factors involved that I’m not taking into account.
Can I sprinkle alfalfa pellets under my fruit trees?
Yes you can sprinkle alfalfa pellets under your fruit trees. If you just have a few of them, of course you can add them now in April. It would take an awful lot of them to give the trees so much fertilizer that they would overgrow. However, the correct time to fertilize deciduous fruit trees with conventional fertilizers is just as the the flower buds swell in spring. Most organic fertilizers, of which alfalfa is one, are slow to act and should be added a month or six weeks earlier. You should perhaps be aware that alfalfa pellets may attract animals who want to eat them. However, once they have rotted and the nutrients have gradually combined with the soil they will add nitrogen to your trees. Thus the nitrogen from alfalfa given to trees now will begin feeding your trees in early summer, which will create more growth. If your trees are starved for nutrients and are not growing well this might be a good thing. I don’t think it will do much harm if they are already growing well and producing good fruit. Many gardeners find that a layer of clean (not salty) horse manure over roots of deciduous fruit trees in fall after leaves fall is a great way to fertilize them since nutrients are washed into the ground during winter. Alfalfa pellets added at that time would be beneficial also.
Have you heard of herbicide residues in alfalfa hay used as mulch?
I’ve used alfalfa hay as mulch for a number of years, but recently a neighbor told me that vegetables he mulched with it became stunted. He had read something about residual herbicide and thought that was the reason.
I think that residual herbicide in alfalfa refers to the fact that farmers use the herbicide on alfalfa or they claim they cannot grow pure alfalfa without weeds. I suggest you ask your farm advisor if it’s safe to use this mulch on vegetable crops and tell him or her your experience.
Unfortunately, I must warn you that the makers of Roundup are one of the main funding companies of the Farm Advisors Office and the California Extension. The Master Gardeners and other groups functioning in the various levels of California Extension work promote the use of Roundup. Farmers say they cannot successfully farm some crops without the use of Roundup. Many people believe Roundup is safe, though people like me are concerned about research proving that it actually lasts longer in the environment than previously thought and may invade our ground water. I am not saying that it causes autism in children because I don’t know, but some people think so. It is true that modern agricultural practices do impact public health, kill bees and cause cancer and various diseases in humans that never existed before the era of modern farming methods and industrial agriculture.
I hasten to add that I am an honorary Master Gardener and I am proud of that designation. I think they are a great group. However. I am an organic gardener. Thus I do not believe in using Roundup and nor do I promote the use of pesticides. The exception to this rule is that I do believe in using dormant spray on deciduous fruit trees in winter ad dormant spray is a pesticide. Despite this fact even organic gardeners should use dormant sprays in winter on deciduous fruit trees. The way it is used cannot leave residual spray on the fruit since no fruit is on the tree when the tree is sprayed.
We feed alfalfa hay to our sheep in pasture. The areas where the hay is placed quickly becomes devoid of vegetation,even when placed for only a day or two and excess is raked up. These bare patches do not grow back in for a year or more. I suspected residual herbicides. On line research indicates herbicides are mandatory for high production of alfalfa hay. My wife rakes the hay into compost piles for future soil amendment . What I am unable to determine from on-line sources is if,when,or on what plants (herbs or woody) this compost is botanically safe.
There is some indication that even manure from animals fed herbicide treated hay is not plant friendly.
Thanks,in advance, for experience or data you can pass on.
Companies such as Monsanto are creating genetically altered crops that contain such chemicals as weedkiller. I had not hear of the problem with alfalfa. This is tragic especially since alfalfa was so beneficial as a mulch and even had the effect of a fertilizer. I wish I knew the answer to your question but I don’t.
Organic is always the way to go!
Thank you for sharing
Great tips!
I buy organic alfalfa for my horses. Sometimes outter edge bales get a little mold on them so I use that for mulch. Works fantastically. Find a big hayfarmer and ask for “kickout” bales these are bales the big trucks toss off and you can get them cheap. Many hay growers have big piles of old hay they will give you. Word of caution, I used very thick hay/straw/alfalfa mulch in my berry patch. I heard
What sounded like a broken wAter line (loud hiss) it was a large rattlesnake. So if you live in snake country be careful about reaching into a thick mulch. Alfalfa mulch feeds and protects and you can definitely find organic growers.
Thank you for your excellent comment. I know everything you said is true since I have used rotting alfalfa bales myself. Here is another note to add: Alfalfa contains nitrogen and as the mulch breaks down it helps to fertilize the plants you mulch with it. Unfortunately, however, this means that some animals such as rats will eat it. When you mulch with alfalfa you might get more rats, mice and voles. Perhaps your rattlesnake was after rodents.
Re use of alfalfa hay. I’ve used it for two years now (because we grow it, so I can get a few bales for free). I’ve heard from a couple of fellow Master Gardeners that it can steal nitrogen from the soil when used as mulch. I haven’t had this experience. But this year, I’m having a devil of a time getting some plants going in this mulch, and I’m wondering if that is true – if that’s one reason why people discourage its use as mulch. I see a difference in plants planted into what I applied to the beds last fall, when I put them to bed over a layer of compost; those plants are fine. But the plants I mulched with a fresh bale (i.e., from last year but never opened) are struggling. We have had a cool wet spring, so the basil could languishing fro that; also, the peppers might be suffering from a bacterial fungus. So hot weather is on the way and I”ve treated with copper fungicide. But now I’m wondering if it’s the alfalfa. I tested the soil for nutrients today but am waiting for the sample to settle. Anyone else having issues with alfalfa mulch?
Alfalfa actually has a high nitrogen content. Ground alfalfa is sometimes used as an organic fertilizer. I suggest letting it completely rot prior to using it as a mulch. Unfortunately it also tends to attract wild animals who like to eat it.
Round up ready alfalfa is what you want to avoid. Of course it is the “weed free” variety. But, second cutting of non GMO alfalfa is usually very clean and not sprayed with any herbicide. I use last year’s hay usually molded or at reduced price. Works beautifully to mulch the garden, between rows. In fact, I get my hay, put down flakes in a row, leaving 2_3 inches between, put potting soil in the space, seed it and cover with potting soil and WOW does that work.
Thanks so much for your super comment based on facts and your own valuable experience.
Hello Pat – Just found your wonderful website after searching for the answer to why my young ultra-dwarf Peach tree, growing in a large pot, only has leaves on one side of the trunk??
I, too, am a Master Gardener since 2003. And a forever organic gardener.
But I’d like to comment on alfalfa as a mulch. I have used alfalfa as a mulch around my roses, especially, and also around fruit trees and in the vegetable garden for many years. I lo most of the alfalfa seed contained Monsanto’s Glyphosate – Round-Up Ready.
Using it to mulch around my roses, fruit trees and vegetables was no longer an option.
https://www.ecowatch.com/monsantos-genetically-engineered-roundup-ready-alfalfa-has-gone-wild-1882155413.html
I switched to straw. I’d rather use alfalfa as it holds together longer and has more nutrients BUT refuse to use anything Monsanto, anything linked to glyphosate.
https://www.foodandwaterwatch.org/news/couple-awarded-2-billion-damages-roundup-cancer-case
Monsanto also is connected to the defoliant used in Agent Orange and there continue to be many lawsuits not only in Viet Nam but worldwide.
https://en.wikipedia.org/wiki/Agent_Orange
I live in Southern California’s High Desert. The weather here is extreme – Summer’s heat and Winter’s cold. Mulching is very important not only to protect the soil from erosion and the baking by the sun, but to add nutrients to soil and plants and save money on and conserve water.
Monsanto’s Round-up, now owned by Bayer,has contributed to the spread of cancers and many other very serious diseases and health conditions; and much soil depletion and destruction worldwide before being banned in many countries.
I urge anyone to check out the many youtube videos of Vandana Shiva, and the vast array of articles of the huge destruction of anything that contains the defoliant – weed-killer- Round-up. It continues to be sold in the stores and used by gardeners.
I could not agree with you more! Thank you so much for your thoughtful and well-informed comment. I think Monsanto and Bayer are monstrous due to the death and destruction they cause all in the name of money.