Best Fertilizer for Thyme: How and When to Feed for Healthy Growth

The best fertilizer for thyme is a mild, balanced liquid such as CompleteGrow All Purpose NPK 20-20-20 Liquid Fertiliser or the gentler CompleteGrow Indoor Plant Food Concentrate. Both provide essential nitrogen, phosphorus, and potassium in equal measure, helping thyme maintain compact, aromatic growth without excessive softness. A 20-20-20 formula supports root strength, vibrant leaf colour, and consistent oil production—the hallmarks of healthy thyme and creeping thyme.

Thyme (Thymus vulgaris) is a hardy Mediterranean herb that thrives in lean, well-drained soil. It doesn’t require heavy feeding, but a light, balanced fertiliser program replenishes nutrients lost through watering and keeps plants vigorous across the growing season.

Why Too Much Fertilizer Can Harm Thyme

Excess nitrogen causes weak, floppy stems and reduces flavour intensity. Thyme evolved in low-nutrient conditions, so over-fertilising can quickly lead to diluted oils and poor aroma. Using a balanced NPK 20-20-20 liquid feed at low strength gives just enough nutrition for steady, controlled growth.

Signs Thyme May Need Fertilizer

Pale or yellow new leaves in spring
Weak aroma after pruning
Slow regrowth or reduced flowering
Potted plants showing decline despite correct watering

When these signs appear, apply a diluted dose of CompleteGrow 20-20-20 Liquid Fertiliser or the gentler Indoor Plant Food Concentrate to revive colour and vitality without overstimulating growth.

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Fertilizing Thyme in Pots and Garden Beds

For garden thyme, one or two light feeds per growing season is enough. Potted thyme, however, benefits from more frequent but weaker fertilization because nutrients leach out with watering. Use a balanced liquid fertilizer (NPK 20-20-20) at one-quarter strength every 4–6 weeks during active growth from spring to early autumn.

Feeding Creeping Thyme

Creeping thyme (Thymus serpyllum) spreads rapidly as a flowering groundcover and has even lower nutritional needs than culinary thyme. Overfeeding encourages leggy growth and fewer blooms. Feed creeping thyme just once at the start of spring with a very dilute solution of CompleteGrow All Purpose 20-20-20 Liquid Fertiliser. This helps establish colour and root density without overgrowth. Avoid granular fertilizers, which can burn surface roots—liquid forms are absorbed gently through the soil and root hairs.

How to Apply Fertilizer to Thyme

Water lightly before fertilizing to prevent root burn.
Mix fertilizer at 25–50% of the normal concentration.
Apply directly to soil—avoid wetting foliage.
Feed early morning when soil is cool and plants are actively transpiring.

For indoor pots or balcony gardens, alternate light feeding with a rinse of plain water to flush mineral buildup and maintain healthy soil balance.

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Best Fertilizers for Thyme & Creeping Thyme

CompleteGrow Indoor Plant Food Concentrate: Perfect for thyme grown in pots, planters, or indoor herb gardens. Its low-nitrogen, mineral-rich formulation prevents leggy growth while maintaining leaf fragrance. Feed monthly at half strength during active growth.
CompleteGrow All Purpose 20-20-20 Liquid Fertiliser: Ideal for established outdoor thyme beds and creeping thyme lawns. Provides balanced macro- and micronutrients for dense, aromatic growth and strong root systems.

Thyme Feeding Schedule

Spring: First feed when new shoots appear.
Mid-Summer: Light top-up feed after pruning or flowering.
Autumn–Winter: Stop fertilizing—allow plants to harden before dormancy.

Final Recommendation

Thyme’s minimalist feeding requirements make it one of the easiest herbs to maintain—just enough nutrition to sustain compact, aromatic growth without excess softness. For home gardeners, pair CompleteGrow Indoor Plant Food Concentrate for pots with CompleteGrow All Purpose 20-20-20 Liquid Fertiliser for outdoor thyme and creeping thyme beds. This combination supports healthy, fragrant plants all year with effortless simplicity.