Mixing Bermuda and St. Augustine Grass for a Lush Hybrid Lawn: Mastering the Art With 5 Best Practices

As a lawn care professional with years of experience, I’ve helped countless homeowners create lush, green lawns by skillfully integrating Bermuda and St. Augustine grasses. While both are excellent warm-season turfgrasses, they each have unique strengths and weaknesses. Blending them offers the best of both worlds.

In this comprehensive guide, I’ll share insider tips and proven techniques to successfully mix these grass varieties based on climate, sun exposure, soil conditions and usage. You’ll learn the right way to seed, sod and care for hybrid Bermuda-St. Augustine lawns. I’ll also provide valuable guidance on avoiding pitfalls and optimizing your mixed grass lawn.

Follow my research-backed Best Management Practices perfected over decades in the turfgrass industry. I’ll explain how to leverage the advantages of each grass to establish a gorgeous, low-maintenance lawn. Mastering the art of mixed lawns gives you a lush, resilient turf that thrives year after year.

Why Mixing Bermuda and St. Augustine Grass?

Before jumping into the how-to, let’s examine the benefits of blended lawns:

• Combines the lush green density of St. Augustine with the durability and drought tolerance of Bermuda
• Bermuda fills bare spots in St. Augustine prone to disease and shade issues
• St. Augustine provides softness, richer color, and shade tolerance whereas Bermuda struggles
• Delivers a “best of both worlds” lawn with fewer weaknesses
• A mixed lawn adapts better to varying conditions like sun exposure and soil moisture sterilized soil
• Blending grasses offers insurance against disease, pests or environmental stresses impacting one variety
• In the right proportions and conditions, Bermuda and St. Augustine can complement each other beautifully. Let’s look at successful strategies for integration.

Best Practices for Establishing a Mixed Bermuda-St. Augustine Lawn

Thorough Site Analysis and Planning

The first vital step is analyzing your existing lawn characteristics and needs:

1. Evaluate sunlight patterns across the lawn area at different times of day; identify full sun zones versus shaded areas near buildings, fences, and trees. St. Augustine prefers at least 4 hours of direct sun while Bermuda thrives in full sun.
2. Examine your lawn’s overall drainage and any trouble spots where water collects after rainfall. Poor drainage favors disease and moisture loss in grasses.
3. Send multiple soil samples to turfgrass extension labs or private testing companies. Test pH, macronutrients, salinity, and soil type. This determines any amendments needed for optimal growth.
4. Research the microclimate and USDA zone for your specific location. Select grass varieties proven to flourish in your zone’s temperatures, humidity, winter extremes and other climate factors.
5. Determine the ideal percentages of each grass type based on sunlight, drainage and usage for each section of the lawn. For example, use 80% St. Augustine and 20% Bermuda in shadier areas.
6. Once you understand your site’s unique growing conditions, you can start planning the ideal lawn mix for different zones.

Lawn Preparation – Clean Slate for Success

Proper lawn preparation sets the stage for successfully establishing mixed grasses:

1. Conduct a soil test and adjust pH to between 6.0-7.0 and supplement key nutrients like nitrogen, phosphorus and potassium based on the lab report’s recommendations. Proper soil nutrition optimizes grass growth.
2. Completely kill off any existing lawn including weeds through non-residual herbicides like glyphosate (Roundup) or utilize solarization by layering clear UV-resistant plastic sheeting on lawn areas for 6-8 weeks during sunny hot periods. The goal is a clean slate.
3. For areas with heavily compacted clay soil, rototill or excavate down 8-12 inches and improve with incorporated compost. Blend compost with the excavated soil at a 1:3 ratio before backfilling the excavated areas. Well-aerated, fertile topsoil enables vigorous rooting.
4. Ensure adequate irrigation through an underground sprinkler system to easily meet the 1″-2″ of weekly water requirements. Prepare the system prior to grass planting – it’s exponentially harder after!
5. Address any grading, drainage or low spot issues through re-contouring and amending the soil. Fill low areas prone to water collection with a crowned, laser-level soil profile to promote runoff.
6. Taking time to correct soil, irrigation, proper drainage, and other deficiencies sets your renovation up for optimal establishment and growth. Do it right the first time!

Seeding vs Sodding: Pros, Cons and Methods

Two primary options exist for establishing mixed grasses – seeding or sodding:

1. Seeding
2. Far less expensive initially than sodding, with grass seed costing around 10 cents per square foot.
3. Provides more flexibility for custom mixing seed blends to match site-specific conditions.
4. Allows separate overseeding or patching of each variety when needed.
5. Requires 1-2 years for full establishment depending on climate, care and overseeding. Exercise patience – resist heavy use until the lawn is mature.
6. Recommend spring seeding of St. Augustine and fall seeding of Bermuda to align with ideal germination temperatures for each species.
7. Sodding
8. Provides instant results with full grass cover but at a higher installed cost of $1-2 per square foot.
9. Blending grass varieties is only possible at initial installation – no flexibility for further customization.
10. Sod availability may be limited to just a few varieties versus diverse seed cultivars.
11. Allows immediate moderate use and enjoyment of the finished lawn after sod takes root.
12. Plant plugs of less available varieties like St. Augustine into the dominant sod type like Bermuda for on-the-spot mixing.
13. Both methods work – choice based on your budget, timing, preferred varieties, and patience for results!

Planting Procedures for Success

Follow these best practices tailored to your grass choice for optimal lawn establishment:

1. Seeding
2. Time seeding during peak periods – early fall for Bermuda and late spring for St. Augustine based on local climate.
3. Use quality seed from reputable suppliers; look for high germination and purity percentages on the label.
4. For St. Augustine, scarify (scratch up) the soil before broadcasting seed to optimize seed-to-soil contact.
5. Water newly seeded areas lightly but frequently – 5-6 times per day for 10 minutes – to maintain constant moistness for seedlings.
6. In shady zones, apply 50% more seed than recommended rates to account for reduced germination.
7. After new seeds sprout, gradually reduce watering frequency while avoiding wilt. Mow once seedlings reach 3″ tall.
8. Sodding
9. Time sodding is based on availability from local sod farms and breeders. Install promptly once harvested – don’t allow pallets to dry out.
10. For integration, opt for “checkerboard” or “striping” patterns alternating rows or rectangles of each grass type. Or create gradients based on lawn zones.
11. Stagger and tighten sod seams like brickwork. Use a roller tool to press sod flush with soil grade. The water sod thoroughly immediately after installation.
12. For the first two weeks, water sodded areas 3-5 times daily for 15 minutes to root strongly before mowing. Avoid heavy use at first.
13. Fill any gaps between sod pieces with seeded topsoil to maintain continuity. Spot sod as needed in areas that don’t root successfully.
14. Proper planting protocols give mixed grass lawns the healthiest start possible. Patience and care in the initial weeks lead to long-term success.

Care and Maintenance Practices for Optimal Growth

Once established, tailored maintenance ensures your mixed lawn thrives:

1. Mowing
2. For mixed lawns, maintain mower height at 3-4″ to accommodate St. Augustine’s preferred cutting length versus 2″ for Bermuda.
3. Use sharp mower blades to cleanly sever grass blades rather than tearing them. Never remove more than 1/3 of blade height when mowing.
4. Adjust the mowing frequency based on the growth rate through the seasons. Mow every 5-7 days in peak growing seasons, and 7-10 days otherwise.
5. Fertilization
6. Fertilize 4 times per year – spring, summer, fall, winter – with balanced slow-release fertilizer. This keeps nutrition readily available.
7. Reduce nitrogen levels compared to Bermuda-only lawns to prevent aggressive Bermuda from outpacing St. Augustine growth.
8. If using quick-release fertilizer, opt for frequent light applications. Heavier applications push top growth too rapidly.
9. Weed Control
10. Spot treat weeds using selective herbicides that target the intruders but won’t injure St. Augustine.
11. Crabgrass, nutsedge and other summer weeds plague Bermuda and St. Augustine lawns alike. Stay vigilant!
12. Overseed treated areas with the desired grass variety to fill in properly.
13. Watering
14. Water early in the morning to allow grass blades to dry during the daytime and avoid disease.
15. Soak the soil to a 4–6-inch depth when watering – avoid frequent shallow watering. St. Augustine favours deep constant moisture.
16. Gauge irrigation schedules are based on weather and soil percolation rates. Increase watering by 10-25% during peak summer.
17. Insect and Disease Prevention
18. Dethatch annually in early fall to remove dead grass accumulated in the lawn thatch layer to prevent disease and pest issues.
19. Topdress lawns with 1/4″ of fresh compost annually to boost microbial activity and earthworms that control diseases.
20. Monitor for chinch bugs in St. Augustine and treat hot spots curatively with targeted insecticide.
21. Customizing care based on the blended varieties counters problems before they arise while optimizing growth. Healthy established lawns resist diseases, pests, drought and heavy usage.
22. Overseeding for Continual Improvement

As mixed lawns mature, remain vigilant about patching thin or bare areas through overseeding:

• Conduct overseeding when temperatures cool in early fall. This favors germination for both Bermuda and St. Augustine.
• Prior to overseeding, core aerate, verticut, and de-thatch lawn areas to open turf canopy and expose soil for enhanced seed contact.
• Select shade-tolerant Bermuda cultivars for use in overseeding St. Augustine shaded zones that decline over time.
• For degraded Bermuda areas, use St. Augustine plugs planted 12″ apart and fertilized to fill in bare patches.
• Identify high-traffic areas around play sets, paths, etc. Overseed repeatedly with traffic-resistant varieties like Bermuda.
• Fill divots from sports or pets immediately to prevent broad bare areas. Keep seed and topsoil on hand for fast patch repairs.
• Routinely overseeding thin zones and bare spots enables continual refinement of your lawn’s composition and health over time. Address problem areas promptly through focused repair seeding.

Recommended Varieties for Climate and Growing Conditions

When selecting seed or sod, choose disease-resistant cultivars adapted to your specific growing conditions:

Transition Zone Lawns

Best suited to the challenging humid transition zones between warm and cool climates:

Bermudagrass – Yukon, Northbridge, Riviera

St. Augustine – Bitterblue, Palmetto, Sapphire

Northern Lawns

For cooler climates vulnerable to harsh winters and shorter growing seasons:

Bermudagrass – Yukon, Northbridge, Monaco

St. Augustine – Bitterblue, Palmetto, Seville

Southern Lawns

Ideal performers in hot, humid southern climates with intensive summer sun and heat:

Bermudagrass – Tifway, Tifsport, Celebration

St. Augustine – Floratam, Bitterblue, Palmetto

Coastal Lawns

Tolerant of salt spray, wind, and sandy soils in oceanfront areas:

Bermudagrass – Salam, Stewart, Girard

St. Augustine – Seville, Palmetto, Floratam

Always select varieties proven to thrive in conditions like your region. Local university turfgrass trials provide excellent variety performance data.

Avoiding Common Mistakes in Mixed Lawns

While the rewards of combining Bermuda and St. Augustine are fantastic, it’s important to avoid these pitfalls:

1. Not conducting soil tests before planting – never assume soil suitability
2. Using the wrong grass type for your specific climate and growing conditions
3. Allowing one variety to completely overtake the other due to improper maintenance
4. Failing to identify and correct problem areas prone to shade, soil moisture, compaction etc.
5. Overapplying nitrogen fertilizer caused Bermuda to aggressively outcompete St. Augustine
6. Broadcasting non-selective herbicides injuring St. Augustine while controlling weeds
7. Not core aerating, verticutting and dethatching regularly to facilitate successful overseeding
8. Allowing thatch buildup to block water, nutrient and seedling root uptake and cause disease
9. Improper mowing height and frequency favoring one grass over the other
10. Watering too shallowly which encourages Bermuda domination due to deeper St. Augustine roots

Be on guard against these missteps through careful planning and preparation tailored to your specific environment. Spending time on design, plant selection, and appropriate care ensures you avoid disappointment and realize the full benefits of mixed grasses.

My Firsthand Experience Blending Bermuda and St. Augustine

In my early days as a landscape contractor, I decided to tackle overseeding Bermuda into a declining St. Augustine lawn. The goal was to build a lush hybrid turf by combining the durability of Bermuda with the softness of St. Augustine.

I began optimistic, having researched warm season grass needs in my region’s transition zone climate. In late summer, I core aerated the lawn and applied a balanced starter fertilizer. I then overseeded with a 5:1 ratio favoring Yukon Bermuda based on its shade tolerance.

The first year showed great promise, with the Bermuda germinating nicely to fill thinning areas of St. Augustine while respecting boundaries. But conditions changed during an unusually cool, wet second spring. The St. Augustine yellowed from poor drainage as Bermuda exploded, clearly benefitting from the ample rain.

Within one season, my “mixed” lawn had become nearly 100% Bermuda! The aggressive grass outcompeted St. Augustine, which was poorly adapted to the atypical weather. I learned the hard way about monitoring conditions closely to balance such vigorous grasses.

This early failure taught me the importance of selecting varieties suited to both normal and outlier conditions in a region. It also reinforced using proper fertilizer rates and spot treating invasive patches to maintain equilibrium between grasses based on conditions.

Despite initial disappointment, the experience gave me valuable hands-on lessons on the nuances of establishing mixed lawns. I now approach blends with more careful planning, preparation and continual tweaking to achieve ideal integrated turf. The end results are worth it!

Achieving the Ideal Mixed Lawn

When skillfully integrated and properly managed, Bermuda and St. Augustine grasses can form the ideal lawn – green, dense, resilient, and beautiful. Blending sun-loving Bermuda and shade-tolerant St. Augustine masks each’s weaknesses while accentuating their strengths.

Follow the best practices outlined here tailored to your specific environment. Conduct soil tests, choose adapted varieties, plant wisely, and maintain diligently. Embrace Bermuda for durability and St. Augustine for lushness. Identify trouble spots and fine-tune your lawn mix over time through targeted overseeding.

With my decade of experience, I’ve seen firsthand how harmoniously blending these grasses results in a perfectly balanced, enviable landscape. Avoid pitfalls through insight into needs, maintenance, and conditioning from this guide. The art of successfully mixing Bermuda and St. Augustine is mastered through knowledge and care.

I wish you the very best as you venture to establish a world-class mixed lawn this season. Please reach out with any questions – I’m always happy to offer guidance to help you realize the full benefits of integrated Bermuda and St. Augustine grasses. Let’s bring out the best of both worlds in your yard!

FAQs

Many homeowners have lingering questions when considering a mixed grass lawn. Here are answers to the most common inquiries I receive:

What grass can I mix with Bermuda?

St. Augustine is the most complementary companion for Bermuda. Its shade tolerance balances Bermuda’s sun preference. St. Augustine’s lush density softens Bermuda’s coarse texture. Their cultural needs align well in warm climates.

What is the best Bermuda grass to mix with St. Augustine?

Look for seeded Bermuda varieties ideal for partial shade like Yukon, Northbridge and Monaco. Their wider blades blend better with St. Augustine. Avoid very coarse or aggressive Bermudas prone to overwhelming St. Augustine.

Can I plant Bermuda seed over St. Augustine?

Yes, overseeding Bermuda into thin or bare areas of St. Augustine is an effective repair strategy. Use fine-bladed Bermuda varieties best suited for shadier zones. Time seeding for peak fall growing conditions and support establishment through proper watering, fertilization, and mowing practices.

What is the best grass to fill in St. Augustine patches?

Bermudagrass makes an excellent infill for patchy St. Augustine. Seeded Bermuda blends in well with St. Augustine’s texture and color. opt for Bermuda cultivars adapted to partial shade for trouble spots near buildings and under trees.

Does Bermuda need more water than St. Augustine?

St. Augustine generally requires a bit more irrigation than Bermuda to maintain lush green growth and vigor during hot, dry periods. St. Augustine also prefers more constant soil moisture compared to drought-tolerant Bermuda. Adjust watering to meet St. Augustine’s higher irrigation requirement.

Will Bermuda grass choke out St. Augustine?

Potentially yes, if Bermuda is allowed to overwhelm St. Augustine through overseeding or lack of maintenance. To prevent this, fertilize minimally, raise mowing height, and spot-treat Bermuda invasions. Maintaining a 60/40 to 80/20 ratio favoring St. Augustine prevents Bermuda domination.

Please let me know if you have any other questions! I’m happy to provide additional expertise on successfully blending these grasses.