Hydroseeding establishes a new lawn by spraying a slurry of grass seed, fertilizer, protective wood fiber mulch, and water onto prepared soil. The first mowing is a major milestone, necessary to encourage the grass to thicken and develop a robust root system. It must be timed precisely to prevent damage to the immature plants.
Establishing the Lawn Initial Care and Growth
Immediately following hydroseeding, the primary concern is maintaining consistent moisture in the seedbed to promote germination. The wood fiber mulch acts to retain water and stabilize the seed. For the first two to three weeks, keep the soil surface lightly damp, not saturated. This typically requires watering two to three times a day for short durations.
This frequent, light watering ensures the seed absorbs moisture to sprout, which often begins within 7 to 10 days. Avoiding water runoff or pooling is important, as excess water can dislodge the seed or encourage fungal disease. This early stage focuses entirely on germination and the emergence of the grass blades, not on anchoring the roots deep into the soil.
Determining the Exact Time for the First Mow
The precise timing for the initial cut depends on the physical condition of the grass, not the calendar date. While many lawns are ready approximately three to four weeks after hydroseeding, this timeframe varies based on temperature, seed type, and watering practices. Waiting until the grass reaches the appropriate height and establishes a secure root system is crucial.
The definitive signal that the lawn is ready is when the majority of the grass blades reach a height of 3 to 4 inches. Cutting the grass too early removes the leaf surface needed for photosynthesis, which generates energy for root growth. To confirm root stability, perform the “Tug Test”: gently pull on a few blades of grass. If they resist and remain firmly planted, the lawn can withstand the force of a mower; if they pull out easily, postpone mowing.
Proper Technique for the Initial Cut
The initial cut must be performed with great care to avoid stressing or damaging the new turf. Follow the “one-third rule”: never remove more than one-third of the grass blade’s total height in a single session. For example, if the grass is 4 inches tall, the mower blade should be set no lower than approximately 2.6 inches.
For the first few cuts, set the mower deck to its highest setting (3 to 4 inches) to ensure a light cut that encourages tillering, which makes the lawn denser. Use a sharp blade, as dull blades tear the young grass, making the plant susceptible to disease and dehydration. Mow only when the grass is completely dry to prevent soil compaction or wet clippings from smothering the fragile seedlings.
Continued Care After the First Mowing
After the first cut, adjust the watering routine to promote deeper, more resilient root growth. Transition the initial light, frequent watering regimen to a reduced frequency with a greater volume of water. Watering deeply and less often encourages roots to grow downward, making the lawn more drought-resistant.
The nutrients in the hydroseed mixture, particularly the starter fertilizer, are sufficient for the first few weeks. A follow-up application of a balanced fertilizer is beneficial approximately four to eight weeks after hydroseeding, or after the first or second mow. This second feeding supports the continued development of the young turf. Continue subsequent mowing using the one-third rule and a high cut height for several weeks, gradually reducing the height as the lawn matures.