Growing thyme and basil side by side sounds perfect, but I’ve learned a few things the hard way that can trip you up. These two herbs have their own little quirks, and getting them to thrive together takes some attention.
I want to save you from the mistakes I made so your garden stays happy and healthy. With a few easy fixes, you can enjoy fresh, flavorful herbs all season long.
Let me share the common pitfalls to watch out for when growing thyme and basil together!
1. Ignoring Sunlight Requirements
Both herbs crave sunshine but have slightly different preferences. Basil demands full sun (6-8 hours daily) while thyme can tolerate partial shade. Placing them in a spot that’s too shady will result in leggy, flavorless basil.
Find a compromise location that receives morning sun and light afternoon shade during intense summer heat. Your herbs will develop stronger flavors and more robust growth when their light needs are properly balanced.
2. Overwatering Disaster
Thyme hates wet feet! It’s a Mediterranean native adapted to dry conditions, while basil needs more consistent moisture. Drowning both herbs with the same watering schedule is a common error that leads to root rot in thyme.
Water the basil directly at soil level, avoiding the thyme as much as possible. Consider creating a slight slope in your bed so excess water drains away from thyme’s root zone toward the more thirsty basil plants.
3. Soil Composition Confusion
Mixing heavy, nutrient-rich soil throughout your herb bed creates problems. Thyme thrives in poor, sandy, well-draining soil while basil prefers richer earth with more organic matter. Using the same soil mix for both leads to stunted growth.
Create microenvironments in your garden bed instead. Add extra compost around basil plants while keeping the soil leaner around thyme. This small adjustment makes a huge difference in how well both herbs perform together.
4. Spacing Errors
Cramming these herbs too close together invites disaster. Basil grows quickly into a bushy plant that can easily overshadow low-growing thyme. Without proper spacing, they compete for resources and neither thrives.
Plant basil at least 12-18 inches from thyme clusters. Allow air circulation between plants to prevent fungal issues while giving both herbs room to expand. Remember that mature basil can reach 24 inches tall while thyme typically stays under 12 inches.
5. Fertilizer Misuse
Heavy fertilizing might seem helpful but actually causes problems. Thyme produces more flavorful leaves when slightly stressed, while basil appreciates regular feeding. Excessive nitrogen makes thyme grow too quickly with reduced essential oils.
Feed basil separately with diluted liquid fertilizer applied directly at its base. Leave thyme unfertilized or use only a very light application of balanced organic fertilizer once in early spring. This targeted approach satisfies both herbs’ different nutritional needs.
6. Pruning Negligence
Letting both herbs grow unchecked leads to problems. Basil requires regular harvesting to prevent flowering and keep producing leaves. Thyme becomes woody and less productive without occasional trimming.
Harvest basil by pinching stems just above leaf pairs to encourage bushier growth. Trim thyme lightly after flowering to maintain its compact shape. Regular pruning improves air circulation between plants and reduces disease risk, while keeping both herbs productive throughout the growing season.
7. Container Constraints
Using containers that are too small restricts root development. Both herbs need space to establish healthy root systems, and competition in confined spaces leads to stunted growth and reduced yields.
Choose containers at least 12 inches deep and 14 inches wide for growing these herbs together. Ensure adequate drainage holes and use a container-specific potting mix. The extra room allows roots to spread without competing for resources, resulting in healthier plants that produce more flavorful harvests.
8. pH Problems
Soil that’s too acidic or alkaline prevents nutrient uptake. Thyme prefers slightly alkaline conditions (pH 6.5-7.5) while basil tolerates a broader range but grows best in slightly acidic soil (pH 6.0-7.0). Ignoring pH leads to yellowing leaves and poor growth.
Test your soil before planting and aim for a compromise pH around 6.5-7.0. Add garden lime to raise pH if needed, or sulfur to lower it. This small adjustment creates a growing environment where both herbs can access the nutrients they need.
9. Seasonal Timing Errors
Planting both herbs at the wrong time leads to failure. Basil is heat-loving and cold-sensitive, while thyme is cold-hardy and established earlier. Starting them together too early means basil suffers in cool spring temperatures.
Plant thyme 2-3 weeks before your last frost date, but wait until soil warms to at least 60°F before adding basil. This staggered approach respects each herb’s temperature preferences while still allowing them to grow as companions through the main growing season.
10. Mulching Mistakes
Heavy organic mulch keeps soil too moist for thyme. While basil appreciates consistent moisture retention from mulch, thyme prefers drier conditions and can develop root rot when surrounded by damp organic matter.
Use inorganic mulch like pebbles or crushed shells around thyme plants. For basil, stick with organic mulches like straw or shredded leaves. This dual approach satisfies both herbs’ needs while still suppressing weeds and regulating soil temperature throughout your herb garden.
11. Variety Incompatibility
Not all varieties play well together! Large-leafed Genovese basil can overshadow creeping thyme varieties, while aggressive spreaders like lemon thyme might crowd out smaller basil types. Choosing incompatible varieties leads to imbalanced growth.
Pair upright basil varieties like ‘Spicy Globe’ with mounding thyme types such as English or German thyme. These combinations have similar height profiles and growth habits, allowing them to coexist without one dominating the other.
12. Pest Management Oversights
Using broad-spectrum pesticides kills beneficial insects that help your herbs. Both thyme and basil attract different beneficial insects that pollinate flowers and control pests naturally. Disrupting this balance causes more problems than it solves.
Opt for targeted treatments like neem oil or insecticidal soap applied only to affected plants. Plant aromatic companions like marigolds or nasturtiums nearby to repel common pests. This integrated approach maintains the natural ecosystem while protecting both herbs from serious damage.
13. Harvesting Imbalance
Over-harvesting one herb while neglecting the other creates problems. Taking too much basil at once stresses the plant, while failing to harvest thyme regularly leads to woody, less productive growth that can encroach on basil’s space.
Harvest both herbs regularly but moderately. Take no more than one-third of each plant at any time. Alternate your harvesting focus between the herbs to maintain balance in your garden bed, ensuring neither one becomes stressed or overgrown.
14. Winter Protection Neglect
Forgetting that these herbs have different cold tolerances leads to unnecessary losses. Basil is an annual that dies with the first frost, while thyme is perennial in most climates and needs different winter care to survive and thrive next season.
Harvest all basil before frost and consider starting seeds indoors for next year. For thyme, apply a light mulch around the base after the ground freezes to prevent heaving. This seasonal awareness preserves your perennial thyme while making the most of annual basil.
15. Companion Planting Ignorance
Missing opportunities to add beneficial companions creates an incomplete garden ecosystem. While thyme and basil grow well together, certain other plants enhance their growth, flavor, and pest resistance when planted nearby.
Add nasturtiums to repel aphids that attack basil. Plant shallow-rooted flowers like sweet alyssum to attract pollinators and beneficial insects. These thoughtful additions create a more balanced, productive herb garden where thyme and basil can thrive together with minimal pest problems.