Spring is a time of fantastic foliage and beautiful blossoms in the City of Trees, but it’s also a time to treat winter damage and prepare your lawn for a long season of healthy growth. Now is ideal for getting your grass ready to thrive through our hot, dry summer.
Treasure your Treasure Valley lawn? Follow these 10 spring tips to make your Boise lawn the talk of the town all summer long.
- 1. Give your lawn a “rake up” call
- 2. Treat lawn diseases
- 3. Send pests packing
- 4. Test your soil
- 5. Fertilize, if needed
- 6. Apply iron to green up your grass
- 7. Turn on the waterworks
- 8. Prevent weeds with pre-emergent herbicide
- 9. Know when to mow
- 10. Prepare your lawn care tools
- Be gentle with your fresh spring lawn
- Get help from a pro
1. Give your lawn a “rake up” call
You probably spent your fall raking leaves, but it’s time to pick up your trusty leaf rake again (it’s a versatile tool!) and give your lawn a hearty wake-up. Once the ground thaws, rake the soil surface of your lawn to give your grass a fresh slate for growth.
A vigorous raking will:
- Loosen matted grass so oxygen and nutrients can reach grass roots
- Remove twigs and leaves that contain fungi and pests
- Give sunlight a pathway to your grass
- Reveal bare patches where grass has died, so you know where to overseed
- Minimize thatch buildup
What’s thatch? Thatch is the layer of dead grass and other organic matter that settles between grass blades and the ground. A thin layer is healthy for your grass, keeping the soil moist and insulating roots from sudden temperature shifts. But, a thick layer of thatch (over half an inch thick) prevents water, sunlight, and nutrients from reaching the soil and can be a breeding ground for pests and diseases.
2. Treat lawn diseases
Before you start spreading seed over bare patches of lawn, it’s important to address the root (or leaf) issue. Spring is the perfect time to treat diseases that have reared their heads over the winter months.
Boise doesn’t get bucketloads of snow, but we get enough for our cool-season grass (especially tall fescue) to be impacted by snow mold along with other diseases.
Here are common spring diseases to look out for on your Boise lawn:
- Dollar spot
- Gray snow mold
- Pink snow mold
- Powdery mildew
- Leaf spot and melting-out
- Fairy ring
- Red thread
Treat diseases as soon as you spot them so your grass can stand up to summer stress. Some diseases require fungicide, while others will disappear with proper watering and fertilization. Check out our “How to Identify and Treat Grass Fungus” article to learn how you can get your lawn looking its best.
3. Send pests packing
If you’ve ever done yard work in Idaho, you’ve met a grub. Or several. They just can’t get enough of Boise soil, and they’ll do a number on your grass. Spring is the time to get rid of grubs and other pests to prevent summer infestations.
The term “grub” actually refers to an assortment of lawn-damaging larvae, but the ones we know are billbugs. Treat your lawn with a systemic insecticide in late May to early June, before adult billbugs have laid eggs. Systemic insecticides are distributed throughout the whole plant so it can defend itself against hungry larvae.
Choose a systemic insecticide that includes one of these active ingredients:
Don’t want to treat your lawn with chemical pesticide? Apply nematodes (beneficial fungal organisms) to kill billbug larvae. It also may be time to rethink your grass type. There are now grub-resistant varieties of fine fescue, tall fescue, and perennial ryegrass that produce a compound that is toxic to grubs. Look for grass seed that is labeled “endophytic.”
While you’re taking care of billbugs, wave goodbye to these common Boise pests as well:
A healthy lawn is uninviting to pests, so a proper fertilizing, watering, and mowing schedule, combined with annual aeration, will keep most pests at bay. If you need to use pesticides, go with a specific, selective one (like fire ant poison) rather than a non-selective variety. You don’t want to accidentally kill beneficial insects like ladybugs and bees!
4. Test your soil
Haven’t been testing your soil? Spring is the perfect time to start. A soil test will tell you exactly what fertilizers and amendments your soil needs for healthy grass and plant growth.
A soil test will tell you:
- Your soil’s pH level and imbalances (acidic, alkaline, or basic)
- Your soil’s nutrient levels and deficiencies
- Salt levels (salinity)
- Soil factors that might be suppressing plant growth
- Amendments to balance your soil and increase nutrient levels
Boise soil tends to be basic (have a high pH), so you may need to add sulfur or compost depending on the results of the test, especially if you want to plant acid-loving plants like cucumbers or rhododendrons.
How often to test your soil: Your soil is constantly changing, so it’s important to test it every three to five years. The University of Idaho’s Analytical Sciences Laboratory offers comprehensive soil testing for a reasonable price, and you’ll receive a certified soil report in five to 15 business days.
Pro Tip: Apply soil amendments at least four weeks before spreading fertilizer to ensure the amendments and fertilizer don’t interfere with or counteract each other.
5. Fertilize, if needed
In general, fall is the most important time to fertilize your Boise lawn, and overfertilization in spring can tire your grass out before summer begins. However, if your grass is looking drab, a nitrogen-rich fertilizer will green it up nicely.
If you need to apply fertilizer in spring, give your grass 0.5 pounds of nitrogen per 1,000 square feet in mid-April to early May. Wait for your grass to start growing before applying fertilizer: Fertilizing too early in the year forces your grass to divert its energy from its roots to its leaves, which can cause nutrient deficiencies and discoloration in summer.
Not sure when or how often to fertilize? Refer to your soil test. It’ll tell you the optimal amount of fertilizer your lawn needs and what schedule to follow. Some lawns require fertilization four times per year, while others only need it once or twice a year.
Fertilizer and the environment: When high-nitrogen fertilizer flows off your lawn during rainstorms, it wreaks havoc on our local aquatic ecosystems like the Snake River and Arrowrock Reservoir. Fertilizer pollutes the water and causes harmful algae blooms and dead zones (areas of low oxygen that kill plant life and leave fish and turtles homeless). Plus, overfertilization is linked to polluted drinking water.
To protect the environment and our water supply, consider an eco-friendly organic fertilizer instead.
Pro Tip: Apply a slow-release fertilizer in spring (rather than a quick-release variety) to avoid unsustainable growth spurts. If your grass stays yellow even after fertilization, don’t panic and spread more fertilizer. Your grass may have an iron deficiency that can be fixed by a few applications of chelated iron.
6. Apply iron to green up your grass
Boise and most southern Idahoan lawns have highly alkaline (basic) soils, which means grass is especially susceptible to iron deficiencies. If your grass, shrubs, or other plants are turning yellow (or black, in severe cases), they’re probably suffering from iron chlorosis.
Apply chelated iron with EDDHA (ethylene diamine dihydroxyphenyl acetate) to green up your yard. Do NOT apply chelated iron with EDTA (ethylenediaminetetraacetate): It isn’t effective in soils with a high pH.
Spray your lawn and plants with iron every two to three weeks as needed.
7. Turn on the waterworks
If you winterized your sprinkler system, now is the time to get your irrigation system going again. Begin watering your Boise lawn in mid- to late April once the ground has thawed and your grass starts to green.
Avoid watering too early in the year, as this encourages shallow root growth. Wait until your grass starts growing before watering, so your grass can withstand summer drought. Once you notice signs of wilting, it’s time to water.
How much water to give your grass: Established Boise lawns typically require 1 to 2 inches of water per week. You can water once a week, or break waterings into two sessions.
- Deep, infrequent waterings encourage strong root growth. Do not water more than twice a week, as shallow, frequent waterings discourage deep root growth and make your grass less drought-resistant.
- Water in the early morning before 10 a.m. to minimize evaporation from the midday sun and prevent fungal diseases.
- Don’t water at night, as it will invite pests and diseases.
Not sure your grass is getting enough water? Test your soil moisture level with a screwdriver. Try to stick the screwdriver into the ground. If it goes in easily, your soil is moist. If it’s difficult to get the screwdriver into the ground, your soil is too dry and you may need to adjust how much water you give your grass or change your watering schedule.
An eco-friendly alternative: As the population of Treasure Valley grows and we experience more frequent summer droughts, saving water is a top priority. To cut your water bill and protect our ecosystems, try a water-wise landscape design. You can reduce water use by up to 80% when you replace thirsty turfgrass with a drought-friendly xeriscape or rock garden.
8. Prevent weeds with pre-emergent herbicide
Before weeds even begin to germinate, apply a pre-emergent herbicide to stop them from growing. An early spring application will prevent cool-season weeds from sprouting, so you won’t have to do much hand-weeding and spot spraying later in summer.
Common weeds in Boise include:
- Cheatgrass (downy brome)
- Green foxtail
- Black medic
- Common mallow
- Broadleaf and buckhorn plantain
Synthetic pre-emergent herbicides like benfluralin, trifluralin, isoxaben, and oxadiazon can be used to treat these weeds. For a pre-emergent herbicide that’s gentler on the environment, go organic and spread corn gluten instead.
If weeds still emerge, don’t panic: You can spray a post-emergent herbicide (organic or synthetic) to stop them in their tracks. Apply post-emergent herbicide when the soil temperature has been at least 55 degrees Fahrenheit for three days.
9. Know when to mow
Just like fertilizing, it’s important to hold off on mowing until your grass starts growing. Start mowing in early May after Boise’s last frost (on average, May 8). You’ll know it’s time to mow when your grass has grown over 3 inches tall.
Be sure not to scalp your grass by mowing too low. Scalping damages your fresh turf, leaving it vulnerable to early-germinating weeds like crabgrass and foxtail.
Once you’ve completed your first mowing, mow on a regular schedule (about once a week, depending on your type of grass).
Follow these Boise grass height guidelines:
|Grass type||Height when |
|3.25 – 4.5||2.5 – 3.5|
|3.25 – 4||2.5 – 3|
|2.75 – 3.25||2 – 2.5|
|4 – 5.25||3 – 4|
|2.75 – 4||2 – 3|
- Follow the one-third rule. Never cut more than one-third of your grass’s height at one time. So, if your grass is 3 inches tall, don’t cut more than 1 inch off the top.
- Leave grass clippings on the ground. They’ll act as an organic mulch, giving your grass a nutrient boost and preventing weeds. You can use a side-discharge mower (just make sure the clippings aren’t too long), or invest in a mulching mower for short clippings perfect for mulch.
- Don’t mow when the grass is wet. Wet clippings can clog your mower, and large chunks of clippings can smother your grass.
- Mow higher during summer heat. In late July and early August, raise the mower height by a quarter to a half of an inch (1 to 2 notches) to encourage deep root growth and reduce heat stress.
- Keep mower blades sharp. Dull mower blades rip out your grass instead of cutting it. This damages grass and can lead to diseases.
10. Prepare your lawn care tools
No string left in your weed eater? Mower blades not as sharp as they were last summer? Now’s the time to get your lawn tools in working order so you won’t have to worry about stocking up on supplies and fixing equipment in summer (when you’ll be plenty busy with other yard work).
Here are some spring to-do’s to check off your list for easy summer lawn care:
- Dispose of old gasoline and refill the tank with fresh gas (if using gas-powered tools).
- Change the engine oil and replace the spark plug and filter (for gas-powered mowers).
- Charge the batteries on your battery-powered tools. Check that they still hold a charge after the cold winter months and replace batteries if necessary.
- Sharpen your lawn mower blades.
- Refresh the supply of string for your weed eater.
- Inspect and tighten bolts and screws.
Be gentle with your fresh spring lawn
Spring is a time of renewed energy and growth, and it’s tempting to rush outside and dive into yard work. But don’t go overboard! Wait for fall to do the heavy-duty treatments like dethatching and aeration. You don’t want to invite eager weeds or stress your lawn before the summer heat.
Don’t plunge into lawn work too early in the year: Trying to make your grass grow while the ground is still frozen will only stress your lawn.
Get help from a pro
Potatoes aren’t the only plants that flourish in the spud state. With the right spring treatment, your grass will soon be growing strong. If you’re an old pro with pesticides and know your way around a sprinkler system, spring lawn care in Boise is a fairly straightforward DIY. Begin planning in late March so you’re ready to roll when the ground thaws in April.
If you’d rather check off your Boise bucket list rather than this lawn care to-do list, we get it. Spring in the City of Trees offers all sorts of adventures, from meeting baby baboons at Zoo Boise to cheering on the Boise Hawks at Memorial Stadium. Call one of Lawn Love’s Boise lawn care pros to rake, fertilize, and mow your lawn.
Main Photo Credit: Hikmet Çınar | Unsplash