Plant Nanny watering tool. Pre-moisten the soil and gently insert the terracotta stake near the center of the plant. The carefully-designed shape of the stake allows it to be inserted into the soil without damaging the plant’s root system. Fill a wine bottle with water and set it neck-first into the stake and the watering process will begin. Know at a glance when to refill the wine bottle by observing the amount of water remaining in the glass bottle reservoir.