How to Keep a Beautiful Lawn in Boise, Idaho

Watering, Fertilizing, Mowing, and More—Local Tips That Work

If you’ve lived in the Treasure Valley for long, you know that Boise lawns go through it all—hot, dry summers, cold winters, and just enough spring rain to keep you guessing. Whether you’re new to lawn care or just looking to step up your game, here are some tips to help your yard thrive.

1. Watering Your Lawn in Boise

Smart watering is key in the Treasure Valley.

Some homeowners turn their sprinklers on every day, but they don’t let the water run long enough, so the grass roots never grow deep in search of water that has soaked into the lower layers of the soil. This can be confusing. You're watering all the time, but the lawn is brittle and doesn't seem lush. There is a simple solution.

For deep, sturdy roots that lead to the results you want, we recommend watering in two to three heavy sessions. Start early in the morning—between 4 a.m. and 9 a.m.—to avoid evaporation loss, and make sure the ground is thoroughly wet.

When watering deeply, it’s a good idea to check for low spots or run off. You don’t want to accidentally flood adjacent properties under the fence. Take a peek and make sure you’re being a good neighbor.

It’s also considerate to follow city watering guidelines. Many parts of Boise and surrounding cities (Meridian, Eagle, Nampa) encourage watering only three or four days per week to conserve water. And, while you’re planning your schedule, remember not to water the day before you mow. Mowing a wet lawn can tear up the ground and cause damage.

As for the type of watering system you should use, we recommend drip lines or efficient sprinkler heads. This helps keep water usage low while delivering moisture right where your lawn needs it. Sometimes we are asked about flood irrigation. If your property is set up for it, flooding can be great for keeping your lawn green, but you’ll want to watch out for low spots that could cause overflow or long-term standing water. We do find that flood irrigated-lawns tend to be uneven from shifting soil.

Tip for new homeowners: If you’ve just moved to Boise, know that most lawn irrigation systems draw from pressurized irrigation—not potable water—so your system might turn on a little later in the spring (typically April).

2. Fertilizing Your Lawn

Fertilizer helps Boise’s cool-season grasses grow strong through the spring and survive the summer heat.

It’s highly debated how often you should use fertilizer. Some people like less, some like more, and many feel passionately about their opinion. But we find fertilizing at least three times per year is sufficient and produces great results. Aim for early spring, early summer (before July, and be cautious if it’s hot outside) and then once in the fall.

We recommend a slow-release, balanced fertilizer to feed your lawn as it wakes up from dormancy in the spring. If you want a quick green-up for a special occasion, you can go to the garden store and pick up a three-day treatment, but know the results aren’t long term and doing this frequently doesn’t encourage strong grass. Also, if you use a quick green treatment, be sure to run your sprinkler cycle shortly after. This helps retain moisture and avoids burning.

The rest of the year, apply a nitrogen-rich fertilizer to keep the lawn green and vigorous. Do keep in mind, a thicker lawn will require more mowing, so be ready for the extra work. Another tip, if your fertilizer contains iron, blow it off of sidewalks, stone, or concrete. Iron will stain orange.

Lastly, avoid summer overload. Fertilizer in July or August can stress your lawn when heat and drought are at their worst in Boise.

3. Mowing

Your mowing routine should support healthy growth and protect your lawn from Boise’s intense summer sun. Here are some tips:

• Keep it tall. Set your mower to 3 to 3.5 inches. Taller grass shades the soil, retains moisture, and crowds out weeds. Don’t scalp your lawn. Boise’s dry conditions mean scalping can easily lead to sun damage and weed infestations.

  
  

• Sharpen your mower blades. Clean cuts reduce stress on your lawn and prevent disease.

  
  

• Mulch if possible. This requires a special blade for the mower, but mulch puts organic content back into your soil and helps hold moisture, leading to a healthier lawn. Don’t overdo it. If the lawn is too long or you don’t have a quality mower, there may be too much mulch, causing ugly build-up of thatch.

4. Weed Control: Stop Them Before They Start

Boise’s weed season starts early, and once weeds take hold, they’re tough to get rid of.

It’s always best to use a pre-emergent like Preen. Apply in February before soil temps hit 50°F. Reapply every 2–3 months through September or October to prevent weed seeds from germinating.

If any weeds make it past your pre-emergent, you can treat them with a targeted herbicide or pull them by hand before they go to seed. Every weed is a weed factory. The moment you have one you will have more. We take weeds seriously.

A note about Roundup. It will kill your lawn wherever you spray it, so don’t use it for spot treatments. Sometimes, we see homeowners spray the entire fence line with Roundup because they deem it a problem area. However, this creates a self-fulfilling prophecy, killing the perimeter grass and making it easier for weeds to grow in the bare dirt.

That leads us to our biggest weed tip: Healthy, dense grass is your best defense. Feed it right and keep it thick to crowd out future weeds.

5. Caring for Soil in the High Desert

First of all, we have never found aeration to be a vital lawn care step in Boise unless you have thick clay soil or major drainage issues. In other parts of the country with heavier rainfall and denser growth, aeration is widely necessary to loosen up compacted soil so water and nutrients reach the roots. But here, we haven’t seen it make a big difference for most properties without preexisting issues. Aeration can’t hurt your lawn. In fact, Boise Parks and Recreation aerates all their parks, so they must find some benefit from it. But we wouldn’t do it just because. There needs to be a reason.

Here are some things we do find useful for keeping healthy soil in every lawn: Similar to mulching, top-dressing your lawn with a very thin layer of compost in April or September builds organic matter and improves water retention. This is an easy step that gets nice results over time. But, really, keeping your grass long enough and deeply watered with strong roots is the best care you can give to the soil underneath.

If you really want to nerd out over your soil, local extension offices or garden centers offer soil testing kits—knowing your pH and nutrient profile helps you fertilize smarter and research your exact situation. Soil can change pretty drastically between properties even in the same city, so it’s interesting to know exactly what you’re working with.

Final Thoughts

Lawn care in Boise isn’t one-size-fits-all—it’s about working with our climate, soil, and water systems. The good news? Once you build a solid routine, your lawn will reward you with fewer weeds, deeper roots, and a whole lot more curb appeal.