Watering in lawn treatments depends on the treatment, the time of year and the weather.
For the majority of lawn treatments applied, no watering is necessary.
Lawn treatments fall into three general categories. Spray treatments (herbicides, fungicides, moss controls and bio stimulants). Granular treatments (fertiliser or lime) and cultural treatments (aeration and scarification).
No spray treatments need extra water. They are water based and need to dry on the leaf to be the most effective.
Granular treatments may need watering in during hot, dry weather. This is to ‘enable’ the granule to begin breaking down and work its way into the soil.

When to water in the lawn treatments
If the grass is dry and no moisture is available for uptake in the soil, a fertiliser granule can ‘burn’ grass. It does this by osmosis, sucking water out of the grass, drying it completely.
This is rare, but it can still happen.
Watering after a treatment can prevent fertiliser burn.
If fertiliser burn is a risk at the time of treatment then your lawn care technician will tell you. If you cannot water the lawn, the treatment should be delayed until rain. Alternative liquid fertiliser treatments are also available during periods of prolonged drought.
Watering for other treatments
The only other scenario in which you will need to water in a treatment is when grass seed is sown. If an area of your lawn is repaired, or the lawn over seeded, extra water may be needed to help the seed germinate. Some spring seasons have been dry in recent times. If this occurs you should water in the lawn treatments. Your lawn care technician will tell you if this is relevant to you.
If you are in doubt about watering in any treatment, ask The Lawn Man.