Key Technical Points for Planting and Managing Cool-Season Lawns

Cool-season grasses are suited to growing in most areas north of the Yangtze River with cold-humid, cold-dry, and semi-humid climates, growing best at 15-25°C, and can tolerate low temperatures and cool climates. The common ones mainly include Poa, Lolium, Festuca, and Agrostis; currently, the cool-season lawns planted in most areas are mixed-sown grasses of these genera.

Cool-season lawns can be established in three seasons of the year, with spring being the best. When establishing, the grass species should be chosen according to the soil quality. Poa and Lolium grass species have higher requirements for soil quality, water, and fertilizer, and are not suitable for establishment in areas with poor soil quality and no sprinkler irrigation. Festuca arundinacea species have stronger drought resistance and stress resistance, and can be established in areas with barren soil and poor water and fertilizer. The grass seed rate is suitably 4-5 kg per mu. When sowing, the seeds should be even, 1-2 seeds per square centimeter; after sowing, straw curtains should be covered to prevent water evaporation. Generally, they sprout in 10-15 days, and the straw curtains should be removed once sprouting occurs.

1. Water and fertilizer management. Cool-season lawns have relatively strict water requirements. Water management should be "wet then dry, alternating wet and dry." Specifically, watering should be thorough so that water seeps down to the root layer, and the second watering should be done after the water has evaporated and the soil has dried thoroughly, avoiding watering multiple times a day with short intervals. During continuous rainy days in summer, drainage should be timely to prevent waterlogging. Cool-season lawns do not have very strict fertilizer requirements; the amount and frequency of fertilization can be controlled according to soil fertility and seedling condition, generally fertilizing in autumn and spring. In autumn, apply compound fertilizer with complete nitrogen, phosphorus, and potassium; in spring, apply nitrogen fertilizer, mainly urea. Fertilizing in summer should be done with special care, and must be based on seedling condition; where the soil is thin and the seedlings weak, apply less, to prevent excessive nitrogen fertilizer causing excessive vegetative growth and disease. After fertilizing, spray irrigate heavily or choose to fertilize on rainy days, and be careful to prevent leaf burn.

2. Mowing. Cool-season lawns grow relatively fast, and generally should be mowed once every 15-20 days. In summer, the number of mowings should be appropriately reduced and the stubble height increased, preferably mowing at 10-12 cm with a stubble height of 6-8 cm. However, if the interval is too long and the grass grows to more than 20 cm, cutting off more than 1/2 at once will affect grass growth and lead to bald patches in the lawn. In addition, lawn grooming should be carried out frequently, with frequent weeding and removal of old yellow leaves and rotten leaves, to increase the permeability of the turf.

3. Control. The insect pests of cool-season lawns mainly include underground pests such as mole crickets, white grubs, ants, and earthworms, and aboveground pests such as armyworms, locusts, aphids, wheat bugs, and meadow moths. Underground pests can be controlled by seed dressing with chemicals, applying poisoned bait, and spray irrigation of chemicals. Aboveground pests can be controlled by spraying 40% omethoate emulsifiable concentrate at 1000-1500 times dilution or 5% fenvalerate emulsifiable concentrate at 5000 times dilution.