Installing sod directly over existing grass may appear time-saving, but it often compromises the health and longevity of your lawn. Without proper soil preparation, roots struggle to establish, and drainage issues can arise. Sodding Canada emphasizes that removing old turf is essential for ensuring strong root contact, nutrient absorption, and lasting results. A well-prepared foundation leads to a lush, resilient lawn that thrives through every season.
Key Takeaways
- Sod needs direct contact with prepared soil
- Old grass can block root establishment
- Poor preparation leads to drainage problems
- Removing existing turf ensures long-term results
Why Direct Soil Contact Matters
Direct soil contact is essential for healthy sod or seed growth. Without it, roots can’t penetrate the soil to access nutrients, water, and oxygen. When grass seed or sod rests on existing grass, that barrier blocks root development, leading to weak, shallow growth. Proper contact with loosened, nutrient-rich soil ensures that roots can anchor deeply and establish quickly. This foundation promotes better drought resistance, disease prevention, and overall lawn health. Whether you’re seeding or laying sod, removing old grass and preparing the soil properly gives your new lawn the best chance to thrive from the start.
Why People Consider Laying Sod Over Grass
At first glance, skipping the removal of old grass sounds like a win. Less labor, faster results, and fewer disposal headaches. Homeowners might think the existing grass will simply die off underneath the new sod and decompose into the soil. However, this isn’t how things work in practice.
Grass is a living, breathing plant, and so is sod. When you stack one layer of living grass on top of another, you’re asking for trouble, especially in a climate where growing seasons are relatively short and conditions can swing from soggy springs to dry summers.
What Happens When You Lay Sod Over Grass?
When sod is installed over an existing lawn, several negative outcomes typically follow:
1. Poor Root Development
Sod needs direct contact with soil to establish roots. When laid over existing grass, the sod’s roots struggle to reach the soil below, and instead of anchoring and growing downward, they remain shallow. This results in weak, unstable sod that may never fully “take.”
2. Oxygen Deprivation
Healthy roots need oxygen. When you stack sod on top of old grass, the lower layer creates a barrier that restricts airflow to both the new sod and the existing grass. This often leads to rot and decay, producing foul smells and promoting fungal growth.
3. Drainage Problems
Layering sod over grass can prevent proper water infiltration. Water may pool between the sod and the old grass layer, leading to soggy patches, mold, or even grass disease. This becomes even more problematic in areas where spring thaws and rainstorms saturate lawns.
4. Uneven Surfaces
Because the underlying grass may die off unevenly, your new lawn can settle in irregular patterns. You might start with a nice, level surface, but a few weeks or months later, bumps and dips appear as the grass underneath decomposes unevenly.
5. Weed and Pest Issues
The decaying layer of old grass can become a breeding ground for pests, insects, and weeds plant. Without removing the existing turf, you’re essentially trapping potential problems beneath the surface, right under your fresh sod.
Cold Climate Challenges Make It Worse
In areas with cold winters and short growing seasons, timing and root establishment are even more important. Sod laid in the spring needs to root quickly to survive summer stress, and fall sod needs to root before the ground freezes. Laying sod over existing grass delays rooting, reducing the chances of successful establishment before the next seasonal challenge rolls in.
Also, snowmelt and freeze-thaw cycles in early spring can expose or shift poorly rooted sod. If your sod didn’t root deeply because it was sitting on top of old grass, it can become loose, dry out, or even wash away in heavy spring rains.
The Right Way to Prepare for Sod
If you want your sod to thrive and give you a beautiful, lasting lawn, proper lawn preparation is key. Here’s what should be done before installing sod:
1. Remove the Old Grass
Use a sod cutter or shovel to strip away the existing grass and thatch. This creates a clean, bare soil surface for the new sod to root into. Removing the old turf also eliminates weed seeds, pests, and disease that may be present in your current lawn.
2. Loosen and Level the Soil
Till or rake the soil to a depth of at least 3–4 inches. Break up compacted areas and remove rocks or debris. Level the area to ensure smooth, even sod installation and proper drainage.
3. Add Topsoil if Needed
If your soil is heavy clay or low in organic matter, adding a layer of quality topsoil can improve drainage and promote healthier root development.
4. Test and Amend the Soil
A simple soil test can tell you what your lawn needs in terms of pH and nutrients. Apply lime, compost, or fertilizer as recommended to give your new sod the best start.
5. Water Before and After Installation
Lightly water the soil before laying sod. After installation, water the sod daily for the first couple of weeks, keeping it moist (but not soaked) until roots begin to establish.
Long-Term Benefits of Doing It Right
While ripping out old grass may seem like extra work upfront, it pays off in the long run. Sod installed on properly prepared soil:
- Roots faster and deeper
- Stays greener and healthier year-round
- It is more resistant to drought, pests, and disease
- Requires less maintenance over time
You’ll also enjoy a more even, professional-looking lawn with fewer surprises as the seasons change.
Professional vs. DIY Sod Installation
While DIY can be rewarding, sod installation requires precision in:
- Soil grading
- Moisture management
- Root establishment monitoring
Choose professionals like Sodding Canada ensures:
- Correct turf removal methods
- Use of premium-quality sod
- Adherence to local climate needs
- Post-installation guidance
Conclusion
Sod is a long-term investment, and it deserves proper groundwork. While it might be tempting to place new sod over existing grass, the risks far outweigh the short-term convenience. For a lush, resilient lawn, start with a clean soil base and work with experts who understand the process from start to finish. Contact us today to schedule your professional sod installation and enjoy a healthy lawn that thrives year after year.
FAQs:
Can I lay sod without removing old grass?
It is not recommended. The old grass prevents proper root contact, leading to poor establishment.
How long does it take for sod to root?
Typically, 2–3 weeks under ideal conditions, provided the soil is prepared properly.
Will new sod kill weeds underneath?
Not always. Weeds can push through the seams or edges if not removed before installation.
What’s the best season for sod installation?
Late spring and early fall are ideal due to moderate temperatures and consistent rainfall.
How often should new sod be watered?
Light, frequent watering for the first two weeks, then deeper, less frequent watering as roots establish.
Can professionals speed up sod rooting?
Yes. Professionals ensure proper soil prep, which accelerates rooting and reduces sod stress.