Growing Hops: Soil Preparation & Composting With Spent Grains

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Before long, any homebrewer with a little yard space is going to start eyeing up the corners of his or her yard and thinking about where to plant some hops. We encourage that urge! As we’ve touched on before, gardening for your homebrew is a great extension of the hobby, and even with a plant as big as hop plants, you don’t need as much space as you think.
Hops are a good plant to grow not only because they can be used in your homebrew, but because they come back every year and as long as they get their start in good soil, they are relatively easy to maintain. Plus, they give you another use for all those spent grains left over on brew day.
The soil is important, though. Hugely important. Most beginning gardeners know how important both sunlight and watering are, but a common mistake is to overlook good soil preparation.
We’re going to help you fix that mistake. In this brief guide, we’ll go over the ideal soil conditions for hops, how to prepare your soil, and some simple home composting methods that will let you make use of the spent grains and other remnants of your brew day to help your plants thrive.

Ideal Soil Conditions for Hops


First and foremost, your hops will require a lot of sun and access to water, so choose a site in your yard that gets full sun – a minimum of six hours of direct sunlight per day, preferably 8 to 10.
Even more important is your soil. Hops prefer soil that is loamy and well drained. This means the soil should be relatively loose, not too compact, and made up of a good mix of sand, silt, and small amounts of clay with plenty of organic matter within. If you cup your soil in both hands, it should feel loose and fluffy, and not too sandy or clay-like. The soil should drain well, so if you have spots in your yard that stay wet long after a rainfall you’ll either need to do some yard work to improve conditions or look elsewhere. Soil that is consistently wet or soggy can cause the roots to rot. Hops are relatively big feeders, so your soil should be rich in key nutrients like potassium, phosphates, and nitrogen. Don’t worry, we’ll tell you how to accomplish that below (though the basics are as easy as adding good compost).
And finally, hops prefer soil with a pH level between 6.5 and 8.0, which is neutral to alkaline. How do you determine your soil’s pH level? Soil test kits can be found at most garden centers and home improvement stores. Don’t spend a lot of money on something fancy. A kit in the $10 to $15 range will do the trick.
Alternatively, you can use a home method in a jiffy. All you need are two bowls, some baking soda, distilled water, and some vinegar. Grab some soil from your garden and place two teaspoons worth in each bowl. Add ½ cup of vinegar to one bowl. In the other bowl, add enough distilled water to make it muddy and ½ cup of baking soda. If neither reacts, you have neutral soil with a pH of about 7. If the vinegar bowl fizzes, your soil leans alkaline and is between 7 and 8 pH. If the baking soda bowl fizzes, it’s slightly acidic, with a pH between 5 and 6.
This latter method isn’t exact, of course, but it will give you a ballpark to work with. So now you know what kind of soil your hops need. If you don’t already have these conditions, no worries. You can get them. Here’s how:

How to Prepare Your Soil


Creating good garden soil is often overlooked but should never be skipped. It’s easier than people realize and has a tremendous impact on your plants, hops or otherwise.
If you have a good source of compost, fantastic. Get some. Some counties or municipalities will provide leaf compost to residents for free. Failing that, garden centers will have bagged compost and manure for relatively cheap.
If your soil is sandy, work some rich organic matter (like compost) into the top few inches of the soil. Aim for a roughly 45/45 mixture, with the remaining 10% made up of peat moss (available at any garden center for super cheap).
If you have soil that is primarily clay, blend in the organic matter, but increase the percentage of peat moss you’re using and add some sandy topsoil to loosen it up. The sand should compromise about 20 to 25% of the mix.
It’s a lot of work, but trust us: start with good soil and your plants will treat you well for years to come. After year one, you can amend each planting spot with about an inch of fresh compost in the fall. This will keep your plants thriving each year and give them the nutrients they need to overwinter well. Also, remember that hop plants tend to spread out horizontally through the ground, so you’ll want to prep a space a few feet in each direction around your plant. The last bit to add to your soil is rock phosphate. This is a great source of minerals your plants need, and they release slowly over time, so you won’t need to replenish it each year. Doesn’t take much, just a small percentage blended in will do the trick.

Adjusting pH Levels

If your soil’s pH is off, no problem. It can be adjusted. It’s best to make these adjustments in increments over the course of two growing seasons whenever possible.
If your soil is too acidic – a pH below 6.5 – you can use either powdered limestone (available at garden centers) or wood ash (right from your firepit!) to raise the pH level. With powdered limestone, add about 7 pounds per 100 square feet of garden space in the fall to prepare for the following spring. (You can add it in the spring as well, it will just take a few months for the soil pH to change.) Use wood ash more sparingly, with just a pound or so per 100 square feet of garden space. Measure your pH again the following year and adjust as needed.
If your soil is too alkaline – and remember, hops don’t mind an alkaline soil, which is why they grow well on the west coast of the United States – ground sulfur, peat moss, sawdust, and oak leaves can all bring levels down. About 1 pound per 100 square feet is a good rule of thumb for all.
You don’t have to be super fussy with any of this. Hops are hardy plants with an amazing will to survive. As long as your soil pH levels are pretty close to that 6.5 – 8.0 wheelhouse, they’ll do fine. The fun part of taking care of your soil comes next. Incorporating your brew day into soil care and maintenance!

Composting Your Grains & Brew Day Waste


Even the most efficient brewers end up with waste at the end of the process. Hop residue, chunks of fruit flesh, herb bags, and of course, spent grains are all common waste items we’re left with at the end of the day. If using your spent grains for baking or dog treats isn’t your thing, you can use them to improve the soil your hops are growing in.
In fact, spent grains are a fantastic source of nitrogen, which is a key nutrient in growing lush green foliage on your plants. The other organic matter mentioned above will all compost well, too.
How to compost really depends on your yard situation. If you have the space for a compost pile, that’s ideal. Even a spot a few feet across on all sides will do the trick (boxed in like a raised bed if possible, but not necessary). If you don’t have or want a compost pile in your yard, you can compost in an old garbage pail. Just drill out some holes in the bottom and sides to provide drainage and you’re all set. If you can’t compost or don’t want to, we’ll have a tip on how to use those spent grains anyway in the next section.
Composting methods can be an article all its own, but the basics are simple: organic matter breaks down into rich soil you can use in your garden. Almost anything that is not derived from animals can be composted. This includes leaf waste, lawn clippings, kitchen waste, and even standard cardboard and newspaper (black and white only). Avoid meat and dairy products, as well as anything soaked in cooking oil. Almost anything else goes. Uneaten pasta. Coffee grounds (great!). Uneaten veggies. Eggshells (excellent!). Pizza crusts. Salad leftovers. And yes, your spent grains!
Good compost is made of a mixture of “browns” and “greens.” Browns are carbon-rich materials, such as leaves, twigs, old newspaper, cardboard, and even wood ash from your fireplace. Greens are kitchen waste, vegetables, lawn clippings, spent grains, coffee and tea grounds, and (believe it or not) hair and fur.
You’ll find many guides that give specific brown to green ratios you should maintain. The truth is, most people need not be bothered with that level of intense scrutiny on their compost pile or bin. For farmers or avid gardeners, sure, but the fact is that even if your ratio is “wrong,” you’ll still get compost in the end. Just ensure you have a mix of both materials and you’ll be good.
Two rules of thumb to keep in mind:
• If your compost starts to stink, there is too much “green” in it. Add some browns and the problem will be solved.
• If your compost is taking too long to break down, there is too much “brown” in it. Add some greens, such as your spent grains, and the process will accelerate.
Otherwise, try to grab and shovel and turn the compost materials over once or twice a week. Over the span of a few months, you’ll see all that mess slowly turning into luscious soil. Depending on your household, you could have one or two hundred pounds of compost to use each fall in amending your soil.

How to Use Compost and Spent Grains


Home composting can be a slow process for the average homeowner. This author, for instance, gets about 2/3 of a 40-gallon garbage pail full of usable compost each year from his suburban household – and yes, it takes the whole year for all that material to break down into good soil. (I use two bins, one for older compost, one for fresh stuff.)
But once you have it, there is nothing better for your garden. Using your compost to help the growth of your hops is easy. Each fall, after you’ve cut back your hop plants, add about an inch of the compost around the plant, roughly two feet in all directions.
And that’s it. No need to even mix it deep into the soil. Rainwater will pull all those nutrients downward to your plants’ roots. The material will improve the soil and help feed the plant as it goes semi-dormant underground for the winter. When the spring comes, you’ll have fantastic growth right from the start. If you do not start composting, your spent grains can still come in handy. Simply spread them out around your plants after you’re done brewing, ensuring it dries first. Once in a while, gently till it into the soil – but not too deep, hop roots are shallower than you realize. Ideally, you’ll periodically add some shredded tree leaves to the same spot. That’s because the nitrogen-rich grains count as a “green,” so the “brown” of the leaf waste offers a little balance.
The same holds true with your spent hops. After you’ve dry-hopped that beer with fresh-from-the-garden hops, don’t throw the cones away. Send them back to nature. Let them nourish the plants that gave you the hops in the first place.
It’s no more complicated than that. Just don’t add pounds and pounds worth every week or two. It will start to smell. At that point, just start a compost bin or pile.
The bottom line here is that spent grains and used hops don’t need to be waste. If you’re growing hop plants, let your brew day work for you in more ways than one. Utilize that brew day waste to develop bigger, better hop plants that provide you with bigger, healthier harvests. Rinse, repeat, and you’ll enjoy fresh-hopped homebrew for years to come!
Great article, Eric. I thought it was particularly interesting, since I am a soil scientist and a hop-growing homebrewer. I have a couple of suggestions to add. Most states offer soil testing through their land grant university. If people are interested in finding out more about their soil's fertility (nitrogen, phosphorus, potassium, etc.), texture, etc., then they should be able to pick up directions for sampling soil, and a sample box they can use to submit it to a lab for testing. This is usually very cheap, and in some states it is free. They will get the results back in about a week or two. Most state extension services also have extension bulletins with suggested rates for fertilizing and liming based on those soil test results. Too much fertilizer can be a bad thing, so getting soil tested is important.
Also, hops are susceptible to fungal problems in warm areas with high humidity. Most hops are grown in the Pacific Northwest because of the dry air and long days. If people do live in warm areas with high humidity, I suggest they make sure the varieties they plant are varieties that have been selected to resistance to various fungal infections common to hops. Placement in the yard is important as well. An area that is both sunny, and that allows for free air circulation to keep the bines dry will help a lot to keep fungal pressure down. Also, only water the hops early enough in the day to allow them to dry off completely before the sun sets.
Thanks for the article!
Very informative article! I enjoy homebrewing and gardening and am in my third year of growing hops. In particular I thought the pH testing with vinegar and baking soda was interesting. I'm just starting to pay more attention to the quality of my soil. As you mentioned it's an important aspect but something I had kind of overlooked. It would be great to put my spent grains and homegrown hop material back to work in another way.
Fantastic advice, Colby, especially pointing people towards potentially free soil tests in their area. That's something I should have considered and included. Hopefully people will scan the comments!
My area gets fairly humid in the summers, so what I typically do is prune all the leaves and sidearms off the first few feet of bine. Helps a lot with airflow. Fingers crossed, I've been lucky so far.
Just curious - should the spent grains be dried before adding to a compost bin, or just out of the mash tun and into the compost bin?
What about the break material in the kettle after the wort is transferred - compostable as well? What about the yeast/hop trub in the bottom of the fermenter after the beer is transferred?
We're new to composting, and I'm not sure how best to use my homebrewing waste for this purpose.
Hey Jason,
No need to dry them first. It's fine to put them in the compost right out of the mash tun. Compost actually needs some moisture to do its thing, so some wet grains certainly won't hurt.
And yes, you can absolutely compost the break material as well. Same thing with hop cones you've used for dry hopping, and fruit you used in secondary, and even the sludge from the bottom of your primary once your beer is done. It is all compostable and will break down into good, health compost.
The one thing to avoid is to ensure things have somewhat cooled first. Items/liquids near boiling levels can kill off the microbes that are essential to the composting process. Let those grains, for example, cool to below 150 or so before tossing them in. A healthy compost pile can actually heat up on its own, with desired temps between 120 and 140, but more than that isn't good.
Good luck!

Latest posts