The Best Type of Soil for Growing Garlic

Garlic leaves sprouting from the ground closeup

The Spruce / K. Dave

Soil is an important factor when looking to successfully grow any garden vegetable, and especially so when it comes to fostering large, good-tasting bulbs of garlic. To start perfecting your mix, you need to first determine what kind of soil you have in your garden by conducting a soil test. Doing so can help you determine if you have the best soil mixture for garlic and, if not, what you need to do to make it better.

If your soil isn't perfect, garlic is a very forgiving plant and can survive even in marginally decent soil. Plus, certain methods—like feeding the soil with organic fertilizers and using cover crops—can help improve poor soil, meaning you'll be on your way to a rich mixture in no time. Follow these easy tips for the best soil possible.

Foster the Right Texture

Garlic grows best in loose, well-draining soil. Sandy loam is the ideal type for growing garlic, but plenty of small farmers also do well with clay soils. If you have too much clay, however, you may find yourself dealing with a moisture problem. Garlic does not grow well in standing water and tends to rot if it has "wet feet" for too long. To solve this problem, try growing it in raised beds, and/or increase the sand and organic matter present in the soil.

Another possible issue with clay-dense soil: Your garlic bulbs will be dirty and therefore harder to harvest. Clay tends to cling to the paper-like outer skins of garlic bulbs and can be cumbersome to remove. It can also make harvesting garlic more difficult, especially if the ground is dry and the clay has hardened.

To achieve that covetable loose soil texture garlic bulbs love (they need room to spread their feet), you can till your soil or plant cover crops. Also known as "green manure," cover crops help to add nutrients to your garden as well as help loosen the soil with their powerful root system. Cover crops ideal for a smaller garden include winter rye, buckwheat, sorghum-sudangrass, clover, and hairy vetch.

Garlic bulbs sitting on sandy loam for growing

The Spruce / K. Dave

Nail Down the Soil Nutrients

Garlic is more like potatoes than onions in terms of how it responds to pH levels and the nutrient balance in its soil. Typically, it grows best in soil that has a neutral to acidic pH level, specifically around 6.0 to 7.5. Garlic also needs several unique nutrients to thrive in your garden. Nitrogen—often found in organic manures—is vitally important during garlic's initial growth phase as it emerges and spreads its leaves. Phosphorus aids in root development, while potassium is critical for leaf growth and healthy bulb formation. Lastly (but certainly not least) is sulfur, whose compounds are directly related to garlic's unique healing benefits and flavors. It's so important, in fact, that many gardeners and farmers add sulfur to their soil by sprinkling gypsum over their beds in the spring, after the plants have emerged and begun to leaf out.

Amend With Manure

When adding manure to your soil (which helps to boost the nitrogen in your mixture), use caution on the timing—it shouldn't be added too close to harvest. Organic certification usually requires applying it no sooner than 120 days before your harvest, as antibiotics, drugs, and GMO residue from animal feed take time to break down in the manure.

When it comes to amending your soil with manure, you have several options on the type—cow, poultry, and horse—each providing its own benefits and instructions.

Manure added to soil closeup

The Spruce / K. Dave

Cow Manure

Cow manure is among the most common options, making it very easy to find both commercial and specialty brands. Three weeks prior to planting your garlic, spread bagged cow manure (or have larger fields sprayed)—by the time you're ready to plant, the smell will have dissipated enough that planting is not an unpleasant chore. Additionally, this time gap will also let the nitrogen settle so that it doesn't shock the cloves when planted. Turn under the cow manure shortly after spreading so the nutrients don't evaporate.

Poultry Manure

Poultry manure, such as chicken manure, boasts the most concentrated source of nitrogen of any manure. Buying or using organic manure is best if you can manage it because there are so many chemicals and GMOs used in feed. Poultry manure doesn't evaporate like cow manure, so it doesn't need to be turned under as quickly as cow manure. However, it's still important to mix it into the soil before planting, especially since nitrogen is so concentrated.

Horse Manure

Composted horse manure can also be a good source of nitrogen for your soil. When selecting this option, make sure you know what drugs, if any, have been given to the horses—whatever they have been given will typically be shed in their manure and go right into your soil.