Watering schedule

How often to water Grosso lavandin (Lavandula x intermedia 'Grosso') — the schedule

Also called Grosso lavandin, Fat Spike lavender, Grosso lavender.

More about grosso lavandin

Watering at a glance

Base rhythm	Weekly for the first season; every 3–4 weeks or less once established
Spring / summer	Spring and summer: water deeply but only when the top few centimetres are properly dry — roughly weekly in the ground, more often only for pots in heat.
Autumn	Autumn: cut right back as growth slows; established plants need very little.
Winter	Winter: keep nearly dry, especially in pots — wet winter soil is the classic killer of rosemary, lavender and thyme.
Light	Direct sun (at least 4-6 hours)

About Grosso lavandin

Lavandula x intermedia 'Grosso' · also called Grosso lavandin, Fat Spike lavender · herb

The world's most commercially grown lavender cultivar, 'Grosso' dominates the essential-oil industry of Provence with its exceptionally large, fat, deep-violet flower spikes and very high linalool oil yield. A vigorous, long-lived lavandin with a strongly sweet-camphor fragrance, it makes a magnificent garden plant for large borders, lavender fields, and dried-flower harvest.

Ideal humidity: Low (20–45% RH)

Watch for — Root rot: The single greatest killer of 'Grosso' outside its native range. Overwatering or poor drainage causes rapid collapse. Site on a slope or raised mound, plant through gravel mulch, and never irrigate established plants unless in severe drought.

The watering schedule, season by season

Grosso lavandin is a lean, sun-loving Mediterranean herb — it grows best kept on the dry side and rots fast if it is watered like a leafy plant. The base rhythm for grosso lavandin is weekly for the first season; every 3–4 weeks or less once established, but the real interval moves with the season, the light and the pot — so treat the figures below as a starting point and always confirm with the plant itself.

Spring & summer (active growth): Spring and summer: water deeply but only when the top few centimetres are properly dry — roughly weekly in the ground, more often only for pots in heat.
Autumn (slowing down): Autumn: cut right back as growth slows; established plants need very little.
Winter (rest / dormancy): Winter: keep nearly dry, especially in pots — wet winter soil is the classic killer of rosemary, lavender and thyme.

Extremely drought-tolerant once roots are established. In France's Drôme and Vaucluse lavender regions, plants receive minimal rainfall in summer and thrive. Irrigation is only applied during establishment. Waterlogging at any time of year is fatal.

Want this turned into a live reminder that adjusts to your home and the weather? The Growli watering calculator takes your pot size, light and season and returns a starting interval for grosso lavandin in seconds.

How to tell grosso lavandin needs water

A calendar is the worst way to water grosso lavandin. Check the plant and the soil instead — for this species, look for these signals in order:

The top 3-4 cm of soil is fully dry and the pot is light.
Foliage looks slightly dull or limp in heat (recovers fast once watered).
For potted plants, the rootball has shrunk slightly from the sides.

The most reliable single check is the first one on that list. When two signals agree, water; when they disagree, wait a day and look again — under-watering grosso lavandin for a day is almost always safer than over-watering it.

Overwatering vs underwatering grosso lavandin

The two failure modes can look alike at a glance, so check the soil weight and wetness before you decide. For grosso lavandin specifically:

Signs you are overwatering

Yellowing, blackening or dropping lower foliage; a sour, wet pot.
Soft, rotting stems at the base — often fatal in rosemary and lavender.
Sudden collapse despite "looking thirsty" (it was actually drowning).

Signs you are underwatering

Crisp, brittle, browning foliage and stalled growth (less common — these herbs are drought-hardy).
For young, unestablished plants only, wilting in extreme heat.

Overwatering and rich wet soil are what kill grosso lavandin, not drought. It evolved on dry, stony hillsides — err on the side of too little.

Water quality notes

Tap water is fine for grosso lavandin; drainage and restraint matter, not water type.

Seasonal and environmental adjusters

Every figure above shifts with the conditions in your home. For grosso lavandin, the levers that matter most are:

Sharp drainage is everything — grit in the mix and a terracotta pot keep it alive.
Established plants in the ground are highly drought-tolerant and rarely need watering at all.
Pots dry faster and need more attention than open ground, but still let them dry between waterings.

Pot choice is part of this too — work out the right size with the pot size calculator, since a pot that is too big stays wet long enough to rot the roots of grosso lavandin.

Grosso lavandin watering — frequently asked questions

How often should I water grosso lavandin?

Water grosso lavandin weekly for the first season; every 3–4 weeks or less once established. Spring and summer: water deeply but only when the top few centimetres are properly dry — roughly weekly in the ground, more often only for pots in heat. Winter: keep nearly dry, especially in pots — wet winter soil is the classic killer of rosemary, lavender and thyme.

How do I know when grosso lavandin needs water?

The top 3-4 cm of soil is fully dry and the pot is light. Foliage looks slightly dull or limp in heat (recovers fast once watered). For potted plants, the rootball has shrunk slightly from the sides. The single most reliable test for grosso lavandin is the first signal on that list — checking the soil or the plant directly always beats watering by the calendar.

What does an overwatered grosso lavandin look like?

Yellowing, blackening or dropping lower foliage; a sour, wet pot. Soft, rotting stems at the base — often fatal in rosemary and lavender. Sudden collapse despite "looking thirsty" (it was actually drowning). Overwatering and rich wet soil are what kill grosso lavandin, not drought. It evolved on dry, stony hillsides — err on the side of too little.

What are the signs of an underwatered grosso lavandin?

Crisp, brittle, browning foliage and stalled growth (less common — these herbs are drought-hardy). For young, unestablished plants only, wilting in extreme heat.

Can I use tap water on grosso lavandin?