From our perspective as Lobelia erinus plants confined to a pot, our relationship with water is one of delicate and constant negotiation. Our fibrous root systems are extensive for our size but are trapped within the limited soil volume you provide. We cannot send roots deeper to seek moisture during dry spells, nor can we spread out to access water from a larger area. We are entirely dependent on your care. Our primary need is for consistently moist soil. This does not mean saturated or waterlogged, which is just as perilous as being dry. The ideal state is a root environment that feels like a well-wrung sponge—hydrated but aerated.
We communicate our hydration status clearly, if you know how to observe. When we are thirsty, our leaves will be the first to tell you. They will lose their turgor pressure, becoming limp, wilted, and soft to the touch. This is our urgent plea for water. However, please do not wait for this signal to become severe, as repeated wilting causes us significant stress and can stunt our growth or reduce our flowering. Conversely, if our leaves begin to yellow, particularly from the base of the plant upwards, and the soil feels persistently soggy, we are likely drowning. This yellowing is a sign of root distress, potentially leading to root rot, where our vital oxygen-absorbing root hairs are dying.
Our watering schedule is not fixed; it is a rhythm dictated by our environment. The size and material of our pot are crucial. A small clay pot in full sun will have us needing water perhaps twice daily in summer, as terracotta is porous and moisture evaporates quickly from the soil and the pot itself. A larger plastic pot in the same location will retain moisture longer. The intensity and duration of sunlight we receive is the greatest driver of our water consumption. More sun means more photosynthesis and more water pulled through our leaves via transpiration. Seasonal changes are also critical. Our water needs peak during the hot, long days of summer and diminish significantly as temperatures cool and daylight shortens in autumn.
The method by which you water is as important as the frequency. We prefer a thorough, deep watering that moistens the entire root ball. Please apply water slowly to the base of our stems, avoiding wetting our foliage, as this can encourage fungal diseases. Continue until you see water escaping freely from the drainage holes at the bottom of the pot. This process ensures that all of our roots, not just the surface ones, have access to moisture. It also helps to flush out any accumulated salts from fertilizers. Allowing the top half-inch to one inch of soil to dry slightly before the next watering is a good practice to prevent overwatering while ensuring our root zone never completely dries out.
