Your shopping cart is empty.

Best mulch for tomatoes?

May 16, 2012

I know there's a thread on soil forum, but wanted to know specifically for tomatoes. I've used wood chips (free) in the past, but they tend to grow mushrooms and I wonder if the fungi contribute to some diseases (of course a bacterially-dominated compost could also contribute to bacterial foliar diseases then too, right?).

Don't have enough leaf mold, compost or wood chips this year so I'll have to buy something - at least to last the first month, after that I might be able to get some spoiled hay - though it will be first cutting and so likely to have seeds (grass and weed) in it.


Comments (54)
  • digdirt2

    Sq. bales or round? Round bales - 1 will last you a couple of years or more. Square bales - 5-6 will be plenty.


  • capoman

    My best preference is composted pine bark when I can get it. I also use wood chips that have been composted with clover/grass. Most of the pine bark I can get my hands on though goes to my containers where it is even more useful. At least composted wood chips/clover/grass is something I create from my own yard waste.

  • 2ajsmama

    Thanks Dave - most people have square bales around here (and I'm not sure how big they are - 4x2x2?). I did see an ad for free round bales but that was posted a month ago and they are long gone.

  • luvahydrangea

    At home I usually just use grass clippings, at my community garden (first year for that) I am using the free wood chips they provide. Is there a difference between hay and straw? I thought they were the same.

  • 2ajsmama

    Well, I've got four 98ft long beds, 1.5 of them are filled with potatoes right now, the other 2.5 are covered with burlap but I don't know how it would work to cut holes in the burlap (right now they're bags, so double layer) and tranplant into them. When I planted bare root raspberries a couple weeks ago I cut the bags down the sides and laid them out in a single layer, cut holes where I was putting the raspberries and stuck my finger down to mark it, then planted the canes and put the burlap over. But I think I'd cut bigger holes (as big as the pot) to plant tomatoes and peppers.

    I covered the raspberry burlap with partially-decomposed leaves (compost not finished yet), otherwise the burlap tends to blow in the wind. The burlap bags on the longer beds are topped with composted manure and rocks, but some still blew off or the edges folded back. And I don't want to leave the manure on top - it's pretty much humus and the weeds will grow right in it! In fact, there are some weeds growing under the double layer of burlap, though they're pretty pale and scrawny.

    But I am picking up 10-12 bales tomorrow and we'll see how much the 2nd person has. If I open them up and leave them out in the rain next week (yes, 3 more days of rain in a row next week too!) should it rot enough not to worry about weed seed? Leave the burlap on underneath?

    luvahydrangea - hay is tall grass (various kinds) that's been cut and left to dry, 1st cutting tends to have seed heads in it, later cuttings are made before the grass can go to seed again. Straw is the stems of grains like oats (may grow some of those next year so I have my own straw) or wheat that has had the seed heads cut off and/or threshed for the grain, so all you have is stalks, and generally the fields are kept pretty much clear of weeds (though you have to be careful with hay too, and ask if there are any persistent herbicides that have been used - in fact, I forgot to ask about this hay!)

  • Bets


    Straw is the stems left after the kernels are harvested from grains like wheat, oats, barley, and similar crops. It is low in nutrient value as a feed for livestock (or people), but great for mulch because it is high in fiber and does help improve soil when it decomposes.

    Hay generally includes leaf matter and is much higher in nutrient value than is typical with straw. Its very good as a mulch in the garden, though I have seen cautions on using it because of the nitrogen content. The NPK values of alfalfa hay is about 3-0.2-2.5, but it also has other nutrients that are great for the microherd in the soil.

    To me the bigger concern would be weed seeds, but if you mulch deeply, it isn't a real problem. As Ajsmamma said, pesticides residue can be a concern too.

    Alfalfa (and timothy, grass, etc) hay is more expensive than straw.

    I hope that helps.


  • 2ajsmama

    I don't know how much straw and hay are selling for in other areas of the country, but in my neck of the woods feed hay is going for $4-6 a square bale depending on quality, straw is $6-7 for what I believe is a smaller bale. I've seen mulch/construction hay advertised as low as $3/bale, but I don't know if the stuff is all weeds.

  • noinwi

    I don't mean to hijack, but could browned grass clippings be used? I have a pile of grass clippings that the maintenance guy dumped just at the edge of the woods last summer. I didn't "work" it for compost, but it is dry and brown. I asked if this year's clippings could be dumped in a different spot in case I were to use the brown stuff and he obliged. Would there be too many pests(other than ticks)or spores in it to use in the garden?

  • 2ajsmama

    They'd be great if you have enough of them, and don't use herbicides on your lawn.

  • barrie2m_(6a, central PA)

    I'm surprised nobody suggested plastic mulch- yes that is how it is referred to. I lay a few miles if black plastic mulch and if I had to do the same area with the same straw I purchased for my strawberries it would cost $4567.

    Nothing warms the soil like black plastic or controls weeds unless you add slices of straw bales which adds a factor of 10 to the price. In my opinion you are better off planting the cereal grain, preferably rye, and plowing it down in the spring. You'll get more organic matter incorporated this way.

  • homegardenpa

    "To me the bigger concern would be weed seeds, but if you mulch deeply, it isn't a real problem. As Ajsmamma said, pesticides residue can be a concern too."

    I use hay every year and swear by it. I have a friend who grows it on their farm, and I know of other local sources as well. It's $5 per square bale and 8 bales last me for the whole season on all of my gardens. Of key importance are the two points mentioned by Betsy above. I know the sources of my hay since I am buying directly, there are no herbicides used, and I layer deep, 6" or more after it's been spread and wet down. It will compact some over time, but it still remains fluffy and allows water and air to reach the soil.

    Another good point is this: "Hay generally includes leaf matter and is much higher in nutrient value than is typical with straw."

    I have experienced no issues with of the nitrogen content, on the contrary, because of the nitrogen content it breaks down a little more quickly than straw and becomes loaded with worms and other beneficials, and by doing so, it helps add to my soil over time. It'll be broken down a good bit by mid-late season, then I'll add some more hay to keep things going. It serves multiple purposes for my needs: weed control, moisture retention, and benefits the micro-herd.

    I've had mixed Alfalfa / Timothy Grass hay on the garden since early March. Not a single weed anywhere (even though the squirrels like to try to dig in it). This is not to say that some things don't occasionally sprout in the hay, but they usually sprout in the evening, or after a good rain, and since they are not rooted in the soil (just in the hay), they are usually toast as soon as the sun gets hot.

    As an aside, I do also mulch with stockpiles grass clippings, leaves, and homemade compost, but I mostly do that in the fall / very early spring. I do this for two reasons: 1.) Hay looks a little nicer / uniform and 2.) Is less likely to blow away in strong wind (it kind of weaves together like a birds nest). In the winter, the grass, leaves and compost are generally wet-down / covered in snow and wind is more of a non-issue.

  • noinwi

    "They'd be great if you have enough of them, and don't use herbicides on your lawn."

    I can't say there are no herbicides as management has TruGreen come in 4 times a season. They spray herbicide the first time(they just did it this week), and the remaining times they apply granular fertilizer(or so they told me).
    I suppose I can try using the clippings around an expendable plant in a container and see how it holds up.

  • huntoften

    Another vote for plastic film mulch. I use bright silver film and have amazing results with it. It bounces light under the leaves and I have virtually zero insect problems...few aphids, ZERO hornworms. It also cools the soil which is a good thing when we have those 100 degree days.

  • missingtheobvious

    noinwi, it would be a good idea to find out what TruGreen is putting on your lawn. Some herbicides remain longer in the clippings than other herbicides -- and tomatoes are unsually susceptible to herbicide damage. (Daylilies too, in case you have any of those.)

    This is an interesting chart I found on the persistance of different herbicides in grass clippings:

  • noinwi

    Thank you Missing, that's helpful. They gave me a sheet on the formula they used last year but I don't know where I put it. It's called Tri-something and has 2,4-D and something else in it. The grass clippings are just about a year old so they may be usable, but I'll do some more research before I try it. I have a few extra plants so I could sacrifice one in a container and try the clippings there. Thanks again.

  • coconut_head

    I started with dried grass clippings this year when I transplanted my Toms out. Luckily I have plenty, I mow, wait for a day (as long as it's nice and hot and dry) and then rake into piles and pick up.

    A new mulch I am going to try this year on at least a bed or two is my spent pea plants. Once I harvest my snow peas, I will cut all the plants at the soil level and then use the tops as a green mulch for around my tomatoes. The foilage is pretty thick but they should be pretty resistant to matting or compacting too hard. The layer might be thicker than a normal mulch layer, like a good 6-8 inches at the offset. I'll try and document with pictures and anecdotal evidence and conjecture. :)

  • ladon

    How can one know if a bale of hay/straw has pesticides? I purchased one months ago from a local garden center, but I've been hesitant to use it in the edible garden because I just don't know if it's been treated with pesticides. Is it common to use pesticides with hay bales? I'm a city boy...I don't know these things. LOL.

  • sue_ct

    Well I use a commercial Hay product called Mainely Mulch that is sold for organic gardens. It is virtually free of noxious weed seeds also, and has worked very well for me. However, I have a fairly small garden, about 8 x 15 feet, and it is somewhat pricey. Its about 15.00 for a 2.2 cu ft bag. But it does fit all your requirements.

  • homegardenpa

    Before I found my local sources. I bought from a garden center and called the grower (since there was a label tied to the bale).

    If you buy alfalfa hay, then you can be reasonably sure there is no herbicides since alfalfa is very sensitive to herbicide and any herbicide treatment would kill the alfalfa along with the weeds.

  • harveyhorses

    I don't know about big opperations, but most small hay people will fertilize more than do weed control. Craigslist would probably get you right to some local growers, it's cutting time!

  • ladon

    What about using unfinished compost as mulch? Would that have too much nitrogen. I filter my compost at the beginning of every growing season and the stuff that hasn't broken down yet goes into a bin to continue composting. Very often it's bits of bark, leaves, twigs and other browns that are still pretty chunky. The content is mostly brown material and very little if any green. But I'm still concerned about it having too much nitrogen.

  • digdirt2

    We grow and mow all our own hay as do most all our neighbors for winter cattle feed. Can't think of any reason why one would use either pesticides or herbicides on their hay fields. Pests aren't an issue with hay and herbicides would defeat the whole purpose of growing hay.

    Straw is a different matter straw is a food crop and oats, barley, and wheat fields are sometimes treated with pre-emergent herbicides and some pesticides. Assuming proper use both should have long since dissipated by mowing time.

    Using unfinished compost isn't a problem as long as it isn't still active (hot). Otherwise it can have the same issues - N binding and/or burning plant stems.


  • erikkrush

    For those of you that use plastic mulch, is an irrigation system necessary under the plastic or is there plastic that allows water to drain through. Is there a specific product that you recommend?

  • artknarf

    four 98ft long beds is a big area. I have about 10 plants, so I just grow clover and alfalfa around them, and some flowers and basil too. seems to work.

  • davidtigerfan

    For those using hay/straw, how do you prevent the grass growth? I bought a bale of what I thought was straw one year and turned out it was hay. I never had so much grass in my garden as that year.

  • digdirt2

    For those using hay/straw, how do you prevent the grass growth? I bought a bale of what I thought was straw one year and turned out it was hay. I never had so much grass in my garden as that year.

    Hay is only a weed problem if you buy a bale of what is called first cutting hay. It has seed heads in it. Later cuttings don't.

    But even then if it is applied as thickly as recommended - 6-8" - then germination is a minor problem. What seeds do sprout are easily pulled since the roots are very shallow.

    For those of you that use plastic mulch, is an irrigation system necessary under the plastic or is there plastic that allows water to drain through. Is there a specific product that you recommend?

    Yes you need some sort of water system under it or in the rows between where the water will have direct access to the soil. There are many brands available, all about the same. They are rated by the # of years of durability, 1-5-10-25 etc. and price increases accordingly - so it depends on if you will be removing it each fall and if you plan to reuse it.

    Be aware that in southern climes it can cause your soil to over-heat and cook the roots unless it is covered with a thick layer of another organic mulch like straw or hay.

    Since this is a mulch question, there are many threads discussing the various mulches used over on the Soil & Mulch forum here.


  • hankjrfan

    I use grass clippings, it's what I can get for the price of the equipment to cut it and the initial investment of a yard sweeper to collect it. 150-200?? It's a system that is only limited by the amount of grass available. It helps the soil. Everyone's situation is going to be a little different and one should lean towards whatever advantage they may have.
    On the wild field seeds getting into the garden. It would be futile from my perspective to try and eradicate these wild seeds completely. Working around them is easier. For instance, till the plot and plant. As things begin to grow you only keep the area that the plant has the potential to grow to tilled, you let the grass begin to grow in the remaining parts. Those areas can be controlled with a lawnmower rather than a tiller and my opinion that letting it get back to its natural state is good for it, rather than keeping it constantly bare.
    As the plants grow, the areas next to the plants will lose the race to the sun and any grass growing will be insignificant. The failures can be underestimating plant size potential, leaving the rows too narrow to be navigated with a mower. Done that many times.
    Row veggies like tomatoes I used to till up only the planting row itself, but realized after a few years that lots of predators burrow in the soil, so I do now turn over the entire plot at least once a year to increase the mortality rate of any larvae. Other than that it works without an insane amount effort.

  • dhromeo

    I wanted to add my 2 cents to what dave said, I have read a few studies on the different colors of plastic mulch.

    Last year I saw gurneys was selling turbo tomato red plastic mulch, and I got suckered in. "It slices, It dices, and it really really works."

    Needless to say I wasn't a huge fan. The theory is that the mulch helps heat the soil in the spring, and helps suppress weeds throughout the growing season, and the red plastic helps increase the ratio of red:far red spectrum light, they say that if the far red is increased it will poke the plant into making more and bigger tomatoes. The study I found showed no measurable gains in tomato yield between several plastic mulches.

    But the study did mention that optimum soil temps for tomatoes is 85 degrees, and anything above and below that temp hampers fruit production. Above, and below. So this year I used the last of the plastic, and I am trying a little experiment to see what happens.

    I think that the soil temps will rise too high in the summer heat with plastic mulch, and I don't like that water can't penetrate it, requiring an under mulch watering system like soaker hose. I am thinking that if I keep the weeds down until it turns hot for good, and then apply a good layer of hay mulch (I have plenty of hay to spare), that the hay will not only moderate soil temps, keeping them more even, but it will help the soil retain moisture, and help combat splitting and growth surges in the fruit, which is what I had last year.

  • ikea_gw

    I mulch all my vegetables with shredded leaf mulch. Our county collects tree leaves in the fall and pile them at their depo over winter. In the spring they are free of charge for all the residents as long as people go get it themselves. It suppress the weeds reasonably well but the best thing about it is it really helps with moisture maintenance so I hardly ever have to water the vegetables. It does breakdown within a year though so every year new mulch has to be applied.

  • cziga

    I mulch all my flower gardens with the cedar woodchip mulch that you can buy by-the-bag at garden centers. I have been putting off mulching the veggie gardens because I wasn't sure what to use. I cover them with leaves in the fall but they have all broken down by Spring planting time.

    I read somewhere that you weren't supposed to use wood chip type mulches on veggie gardens (like the cedar that I use on flowers) but I've never been quite sure why? Why is wood bad for veggie gardens? or is it not too bad, but just not the best choice?

    I will be on the lookout for straw or hay for this summer. I would use grass clippings but we just don't produce enough to make it a practical idea so I'm looking for something that I can use regularly.

  • jolj

    I mulch my tomatoes & sweet peppers like a No-Till garden.
    1)first I put down compost, mostly coffee waste compost.
    2)then burlap bags which will last all summer.
    3)I am mulching the third layer with Pine straw, leaves & then grass clipping.
    The layers should keep the roots cool or cooler then no mulch. I have ripe tomatoes on May 18,2012, a first for me.

  • hejerry

    I use shredded leaves to mulch everything - veggies, trees, shrubs, whatever. I collect bags of leaves from curb sides during the winter and fall, shred them with a chipper/shredder, pile them in a bin then spread them as needed. They need replenishing from time to time but add beautiful tilth to the soil when they break down. Microorganisms love them too.

  • harveyhorses

    If you use the leaf mulch, can you till it in the following spring?

  • socks

    I scatter lawn clippings in my small suburban garden. Haven't had a problem with weeds, surprisingly. If the cuttings are still green, I spread thinly and keep away from base of plants. Also use it in the roses. I've noticed an increase in worms when I mulch with these cuttings, so much that critters are attracted to dig for the worms (not sure what, maybe skunks).

  • digdirt2

    but I've never been quite sure why? Why is wood bad for veggie gardens?

    Because it can bind up any available nitrogen as it decomposes and it contributes nothing to the soil as it decomposes. No nutrients and no improvement in soil tilth/texture.

    If you use the leaf mulch, can you till it in the following spring?

    Yes although you don't really need to assuming it was exposed to enough moisture the previous fall and winter. You might also need to till in some additional nitrogen source with it to further decomposition.


  • sunnibel7 Md 7

    I want to second what Dave said about the (non)use of herbicides and pesticides in hayfields. Generally it isn't done. One way of not getting the seeds so much is to ask around places that have hay for any spoiled bales. Usually this is old hay, so will have been gleaned by mice, or else it is moldy so the seeds have other troubles. Of course it's a good idea to wear a dust mask if you are breaking open moldy hay bales. But a little time in the sun and the mold soon quits. Well, more likely retreats to the bottom and does its decomposition thing. I was just up at the barn where the neighbor is putting up his new hay, and I get to run off with the old, broken, chewed, and partially rotted bales, woohoo! And he doesn't have to cart them off somewhere just to make room for the good hay. Win-win.

  • harveyhorses

    Sunnibel count your blessings! I miss those days, now I am stuck in suburbia, and all my hay connections are gone.
    Ahh the smell of moldy hay! O.K. come to think of it I don't REALLY miss putting up 1000 bales of hay twice a year, but I miss the perks. :)

  • homegardenpa

    Oh, meant to post this earlier, but for those that worry about weeds with hay, here's a picture what my tomato garden currently looks like with the hay being down since early March (about 3 months).

    The only weeds I worry about are the ones that grow through the fence from my neighbors yard; and there are a few there now - just need to smother them again with some more hay. If you layer if deeply enough, and let it compact, weeds are generally a non-issue.

  • sunnibel7 Md 7

    Harveyhorses: I do, I do! I actually moved out of suburbia so I could get things like hay and manure... But I don't miss the days of my youth and putting up hay in a hot, airless loft, either. I thought about joking with the guys about it this morning, but it is too hot for it to be really funny.

  • ngfam2

    Mulches to Avoid

    Avoid using hay or straw around tomato plants. The hay and straw break down at a rapid pace, releasing large amounts of nitrogen. This can cause the tomato plant to produce excessive foliage with very little fruit production. Weed seeds are also often found in hay.

  • digdirt2

    Respectfully but both hay and straw are excellent mulches for tomatoes. They do not break down rapidly and are used by many just for that reason, myself included, for decades. So I'm curious as to what you base that claim on.

    The N content of hay is quite good but given its slow decomp rate it poses no over-dose threat to the plants but provides a slow steady release of N into the soil throughout the season and into the following year. And straw contains little nitrogen. It is almost pure carbon, often called the "perfect carbon" when it comes to composting, so any nitrogen released by its decomposition is minimal.


  • seysonn

    Pine straw, another name for pine needles. Down south wher there are a lot of pines, it is sold by bale. You can also collect your own from various places. It is weed free and stays dry and at the end of season becomed a good soil amendment. The next best, I think , is straw. But with the straw you get alot of weath and/or rye seeds if you don't mind it.

  • sleevendog (5a NY 6aNYC NL CA)

    homegardenpa...that looks just like my open area where i grow zuks, melon, fall squash, pumpkins...
    I lay down a thick run of newspaper, then hay. I do get a seeding clump or six but not at all like actually weeding. It is also a good soft protective bed for the fruit. We tend to have more rain than drought here in the NEast. Mulch needs seem to be regional and what is available.
    My tomatoes are in a raised bed and i use straw. It is expensive here but clean and only need one bale. It is a large compressed bag sold like peat. Straw is the dried stalks of cereal plants, like wheat. ItâÂÂs a by-product of harvest. If any seeds remain on the stalks, itâÂÂs by accident. Therefore, straw is nutritionally void, and is not animal feed. However, that lack of seeds makes it a fine mulch. The expense is that it is free of pesticides.

    Wood chips don't work in my garden. They might for some. I do use a dump load to path the way to the compost piles. Free here by handing off my address to the road crew when trimming tree branches from power lines. I'll have a big pile within an hour or two. No more mud in the back yard as i have it about one and a half foot thick now. I tried it once around the perimeter of my garden and was good for a year but soon started to break down and was hard to keep up with the weed growth.
    Hay bales are usually fresh and sweet smelling green and used for feed and can be expensive. Lesser quality hay bales from a later harvest are dry and useless and i suppose for animal bedding. Both can be full of seed so i keep it out of my raised beds. Once again a regional thing...dry crispy hay bales are free here.

  • dickiefickle

    Another free/cheap mulch shredded newsprint /paper

  • marcantonio

    i've been using straw, the only problem is it gives rodents a place to hide. can be a problem in more urban areas with rat problems.

  • jolj

    You need a bigger cat.

  • marcantonio

    that's definitly true. when there were alot of ats around it made a big difference

  • jolj

    My garden is covered with oak leaves.

  • marcantonio

    really dont have any at my disposal sure wish i could finfd pine bark fines.

  • jolj

    Pine bark works, takes longer to rot, but thats not a problem.

    Some big box sale it.

Need help with a Houzz order? Call us at 1-800-368-4268 (Mon-Sun)