Straw vs Hay – Which Makes a Better Mulch?

straw-bales-and-hay-bales-for-garden-mulchStraw vs. Hay – In the battle to control weeds, add fertility, and improve the water retention of your soil, is one really better than the other? Well in a word…Yes!

Let’s start at the beginning. What is the difference between straw and hay, or are they essentially the same thing? Many people think they’re identical because they’re both often tied into square or rectangular bales, but a closer look reveals that they’re actually quite different. Understanding these differences may help in your decision about which material better suits your gardening needs.

Straw is the stalk of a cereal crop such as oats, barley, wheat, or rye after harvesting has removed the seed heads. Usually a big machine called a combine harvester will come along into the field. In one smooth operation it chops off the top portion containing the grain, send the grain in one direction for processing, then cuts the straw and collects it until a bale sized block is formed. The straw bale is automatically tied and drops out of the machine, back onto the field for later collection. In many parts of the world straw is seen as a waste product, a secondary by-product of the cereal crop, and is sold for practically nothing. But where I live in Nova Scotia, Canada, it is actually more expensive to buy straw than it is to buy hay because not much straw is produced locally. What straw we have is quickly purchased for animal bedding. We just don’t have the climate for mass cereal crop production.

Hay refers to grass that has been cut while green, dried, and then made into square or round bales. Hay is used mainly for feeding animals when no fresh grass is available. It provides bulk, fiber, sugar, and nutrients to animal diets. The best hay smells sweet, and if you took a handful and got it wet it would still look like grass. Straw almost has an almost exclusively yellow color when it is baled, and just a hint of smell. Hay bales can look like a greenish coarse grass, fine grass, or even flowery and weedy grass; it entirely depends on what plants were cut and dried to make the bales. The quality can vary hugely depending on the skill of the farmer making the bales and the quality of his hay fields. It is very important to get hay which has been dried to the optimum level, so that it’s not crumbly but is dry enough to discourage mold growth. Overly dried hay starts to compost quickly when it is damp, and composting hay bales have been known to heat up and start barn fires.

So now that you know the difference between straw and hay… why would you choose one over the other for mulching your garden? I mean, it’s just mulch, right? The benefits of mulch in a garden cannot be overstated, and if you’re reading this article I assume you already know how terrific it is for controlling weeds, and providing walkways. A good mulch also helps the soil to remain cool and moist longer in summer and can insulate the soil in colder weather. Mulch creates a microclimate over your soil by essentially acting as a blanket to protect it from the harsh drying effects of the sun and wind. All mulches perform this action, including our straw and hay, but did you know that other mulches used around the world have included wood chips, bark, shredded leaves, and even rocks? Yes, rocks. The inhabitants of Easter Island recognized that mulching prevented the wind and rain from eroding the valuable topsoil so they used volcanic rocks spaced out on their fields as a lithic mulch to slow runoff and wind erosion. But I can’t imagine most of us deliberately placing rocks in the garden, can you? I know that in my own garden I’m constantly doing the opposite because every year my garden seems to grow a new supply of rocks.

Surely some of these mulching methods work better than others, wouldn’t you think? Do some work better in areas of wind or rain? Are some better suited for slopes? What about availability? These are all questions you need to answer for yourself and then experiment and see what actually works for you. Planning is a huge part of having a successful and productive garden over the long term. You should choose the location wisely, taking into account the sunlight, type of soil, and the climate. But in reality most of us just have to use whatever we’ve got. Not everyone has 20 acres and can pick the perfect spot. So, let’s just say that you are growing in a typical home garden and the mulches you can most easily and economically get are hay and straw.

The Pros of Using Straw Mulch

Straw is a terrific insulator. The hollow stems retain air and their chopped light fluffy texture allows for easy spreading. In fact, the principal uses for straw in the US over the past 200 years have been for animal bedding, for insulating walls in homes (or building straw bale houses), and for covering the ice in ice houses to act as the insulation so the ice was available for use during the summer. When used in a garden it also tends to remain lighter and fluffier than hay, and it keeps a beautiful golden appearance for quite a long time. The surface remains dry even as the lowest layers touching the soil begin to decompose. Have you ever picked strawberries in a field? Almost certainly there was straw around the bushes and it gave you a good clean place to sit or kneel that felt soft and cushioned.

The Cons of Using Straw Mulch

Straw can be expensive depending where you live and you may not be able to grow it yourself. Straw can also act as a home to rodents because of its fluffy texture. It has a higher tendency to blow away in strong winds when it is first laid unless you try very hard to pack it down. Straw does add some bulk to your soil but it is mostly composed of cellulose and fiber that are left over after the plant puts all its nutrients into the seed heads that were harvested for grain. Consequently, straw adds fewer nutrients back into the soil when it decomposes, and soil borne bacteria tie up the available nitrogen for a longer time to break down the tougher stalks. Because straw is fluffier and makes less direct contact with the soil it takes longer to decompose, which is both a plus and a minus. If you want to add nutrients this is a minus, but if maintaining a cover or walkway is important then it’s a plus. Weeds are more easily able to push through a straw mulch from the bottom due to its fluffy nature, but blown in weeds also won’t land in a moist environment so they do not sprout. You can counteract this effect of weed push through by weeding and putting down some newspaper before laying the straw mulch and then using a thicker layer, perhaps 8 inches thick or more, to provide a darker environment that most weeds simply don’t have the energy to get through.

The Pros of Using Hay Mulch

Hay is readily available and it’s possible to get a scythe and cut your own if you have a grassy area on your property. You don’t need to bale it – just cut it, let it dry, and then fork it into your wheel barrow and wheel it over to where it’s needed. Even long grass clippings can function the same way as hay because they’re essentially the same thing. Hay left over from a previous year is often considered garbage by farmers who want to feed their animals the most recent and more nutritious hay, consequently hay is sometimes available for free during hay season in the summer. You can find it by looking at your local online advertisement site such as kijiji or craigslist or by asking your farming friends. Hay contains a variety of grasses and legumes plus often clover and other flowers including both the leaf and stalk, so the plant nutrients are all there. When hay decomposes it adds significant nutrients to the soil to increase its fertility. It adds a balanced ration of NPK as well as all the trace minerals that were contained in the plant. Hay tends to lay flat and pack down so it decomposes fairly quickly and has more of a sponge effect than straw does, which means that in heavy rainfalls it buffers or slows down the amount of rain that soaks into the soil to help prevent erosion and leeching of nutrients. Because hay packs down densely, the weeds from underneath get smothered and die very quickly. But weed seeds that blow in can sometimes sprout, especially in an older hay mulch that is very damp.

The Cons of Using Hay Mulch

In moist parts of the world, hay mulch has more of a tendency to harbor slugs and snails, so you need to keep a good eye out for them and have a method of removal ready. Hay generally doesn’t harbor mice because it’s too dense. Hay takes on a packed and spongy texture that holds water, so sitting or kneeling after wet weather is likely to leave you with a wet bum. Hay holds moisture, allowing seeds on top to sprout, which is why hay bale gardening is such a great thing. But if you’re trying to suppress weeds do you really want this? And often the hay itself contains seeds that will sprout once they get wet, so you could end up with a living pathway until the dry weather dries out the topmost layers of your mulch again. As hay decomposes it is broken down by various bacteria and other organisms that all use nitrogen, the same as we discussed for the decomposition of straw. So what happens is that these organisms get a new food source (your hay compost) and they multiply rapidly, which depletes the soil of nitrogen. As they run out of food the organisms die and the nitrogen is once again available for the plants to use. So planting directly into a hay mulch without any supplemental nitrogen source available probably isn’t the best idea.

So now that you know more about hay and straw as mulches, which one are you going to choose? In a perfect world the solution is to use both. A thick layer of hay mulch on the bottom where it will decompose and act as a spongy reservoir for moisture, topped off with a few inches of straw that will be a dry layer preventing blown in weeds from sprouting and giving you a lovely dry golden walkway. But we don’t all live in a perfect world, do we? We’re just trying to make the best of what we’ve got, and that’s what makes a great gardener or homesteader – the ability to problem solve. So, I’d suggest that if you have a choice of only one type of mulch that you use hay simply for the fertility it will add to your soil. But as all practical gardeners know, you use what you have or can easily get. Why pay money for straw if a local farmer will give you hay in July for nothing? If you can get it free but you don’t need it all at once then simply put the extra bales out by your garden, throw a tarp over them, and save them for next year. If the hay gets wet and starts to compost itself, it really doesn’t matter. It’s all going in the soil in the end anyways, and the pile of bales can act as a wind break while it waits to be used.

A garden is a living, breathing thing. It evolves from year to year, and as gardeners we are the stewards of the fertility that is in our soil. It depends on us to pay attention and make sure that we don’t take out more than we put back in. After all, we want our gardens to feed us for many years to come and to be places where we can teach our children and grandchildren the mysteries of growing their own food too. Gardens are places where families and communities come together to work, talk, and visit, so we should try to make sure that in addition to teaching the value of work we also find pleasure in being outdoors. Planning the best method of mulching your garden is important for fertility and moisture retention, and it will also significantly reduce the amount of time you spend watering and weeding, which will in turn increase your enjoyment of your garden. A well mulched garden also makes better use of the precious water resources that are becoming scarce in so many places. As a fellow gardener, I encourage you to try new things and experiment with mulches to see what works for you. But most of all, have fun in the garden!

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17 Comments
  • Logan

    This article is well written and informative. This year I did buy a straw bale for mulch among tomatoes and peppers with satisfactory results. In the past I have used both hay and straw in the garden. The “cleaner” you can get straw (few weed seeds) the better. I found with hay, there will always be more weed seeds which simply have to be attended. Even so, it can be a good mulch. I once tried to grow potatoes in heavy hay mulch. The potatoes grew well but were damaged somewhat by centipedes drawn to the damp mulch. Articles like the this one are an excellent help in trying to get the best information on gardening. Good job!

  • Practical use for rock mulch is strawberries on a steep hillside. This works very well for me. As they send out runners after fruiting I tuck them in the good soil in the crevices between the rocks. The berries stay clean and the cat sleeps on the big rock and keeps the birds away.

    I use hay that I cut from my fields for mulch to feed the soil but then I cover that with discarded carpet. It is an 8 foot wide expanse of carpet between the row and the fence but the vines are already climbing the fence mid July. A 4 foot strip of carpet keeps the raspberries from coming up in the pathway. I roll it up, add more hay and roll it back out. Seeds in the hay rot under the carpet. The rain goes through and the man made fibers dry quickly but the moisture is protected from the sun and wind by the carpet. Ask a carpet installer they will often deliver it free rather than pay the dump fee.

  • Robert Valiquette

    I raise goats, chickens and turkeys. The hay cycle begins with feeding the goats. They are picky eaters (believe it or not ), they eat about 33-50 % of the hay and toss the balance aside from the hay rack. This becomes their bedding in the goat houses. The decomposition of the wasted hay, manure and urine provides a heated bedding during winter. This is moved to outdoor composting pad once the bedding reaches 4 ” in summer and 8-12 ” in winter. As the weather drains the top surface of pile of nutrients to core, it becomes more like dry straw. This is transferred to poultry coops for nests and bedding material. Once this bedding is built up, it gets moved to compost pile. The compost gets sent to gardens for spreading after crop harvest to break down chopped crop biomass over winter. Come spring, it is turned into soil for planting season. I reserve some for mid season fertilizing mulch (aka; compost tea and mulch of unbroken-down biomass components). This helps give the plants the needed boost and moisture conservation during flowering and bulk growth. Straw I produce from cutting tall dried weeds and grain stalk is used as base for hay compost and garden weeds composting. I also use garden weeds compost for growing my potatoes in. After growing potatoes, melon/cucumber/squash is grown in it.

    I started with 73 % clay soil 10 years ago. Today the clay content is about 48 %. My aim is 25-33% clay without going broke to get there. This year I had 3.5 tons (7 pick-up truck loads) to add to my 1/2 acre garden. I withdrew 1.5 tons of produce last year. This gives me a surplus of 2.0 tons of biomass to garden. Now only if the darn weather would cooperate!

    • That’s an amazing system you’ve got working there. I’m humbled! You’re a good example of someone should has put some thought and planning into their system to get the most out of it. Nice work.

  • Anne

    Where in Nova Scotia do you live, Elizabeth? I live in Halifax and travel around the province regularly for my job. When time allows, I’d love to see your homestead.

  • Jim

    Not sure I understand this statement please clarify.
    Overly dried hay starts to compost quickly when it is damp, and composting hay bales have been known to heat up and start barn fires.

  • Russel

    I use pinestraw for my passage ways instead of hay or straw. It smoother like hay but stay dry like straw and breaks down slow as well as doesn’t blow or wash away. Doesn’t add nutrients but thats what manurer, compost, and fertalizer are for.

  • Judi S.

    I just read on this website that you shouldn’t have a straw bale garden because of the toxic herbicides used on the crop that the straw comes from. Wouldn’t that also apply to using it as mulch for strawberries? I have been using it for mulch on my strawberries and am wondering what else I should use. Thanks.

  • Bob Williams

    Jim’s confusion is justified. The statement about spontaneous hay combustion is wrong. It’s not overly dry hay that overheats it’s wet or green hay, and that can be because of loose bailing but more often by not letting green cuttings dry out enough before you bail. I also thought there would be more of a definitive answer to which is best and all I got was, “well, it depends”. You also mention “long grass clippings” as if shorter clippings are not useful. Most mowers mulch the clippings as you cut but even short clippings can be raked up and used unless you cut too often to make it worthwhile. I prefer clippings for mulch over straw or hay because it’s easier to work with.

  • Max Anderson

    The statement about spontaneous hay combustion is correct but can be mis-read. Overly drying the hay means the cells die and lyse, so that if water is put back in later it makes a sort of soup in which bacteria thrive initially, after which the bacterial enzymes can act generating a lot of heat quickly, becoming a self-reinforcing cycle, as the heat in turn speeds up the enzymatic activity. By contrast, if the hay is not overly dried, many cells may go into suspended animation and not lyse, so that if enough water is added back to enable rotting the bacteria and fungi can only decompose the cells and generate a little heat slowly over a long period. This is less likely with straw because the straw has a lot less nutrients for the bacteria to get started in the first place, the nutrients having been transferred to the grain by the plant and maybe leached out of the dead stem cells by any rain before harvest.

  • Max Anderson

    PS Just to clarify, Bob Williams is right in that hay fires are from baling too wet, it’s just that it’s important to not (over-dry and then let the hay get damp again) before baling. In the Annapolis Valley it’s seldom hay would get over-dried anyway. The main thing is to get it dry and keep it dry.

  • Carol Nieman

    This is the best source I’ve read concerning Straw and Hay differences. That said, I’m looking to protect my grass near the porch. We bought an old house and that area is quickly becoming a mud patch. I was looking for information on which material to use. I’m understanding that straw would work but would like any additional opinions on this matter.
    Help???
    Thanks all.

  • Adahdah

    Hello this is yafa feed products trade we are import wheat straw from many countries we need wheat straw cfr aqaba port Jordan

    Yafafeed@gmail.com

  • Muddy

    Thank you,,, what a great article

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