The small color photo of the fire fern in the Wilson catalog does not adequately portray the deep-red foliage of this delicate indoor plant. Given sufficient light and sun, its color surpasses that of the finest red maple.
Through spring and summer the fire fern, red oxalis, flowers almost continuously, bearing dozens of tiny pure-yellow blossoms. It must have sufficient water, because its water requirements are higher than for other common indoor plants. Fire ferns, two in a clay pot, grow well in a mixture of one-third coarse sand, one-third garden loam, and one-third compost or lead mold. This can be topped with a pebble mulch and a small clamshell fitted among the pebbles.
This beautiful compact plant must have light, and the more sun it receives, the darker its leaves.
To provide air and space, usually the inside window is open, leaving the storm window between the indoor plants and outdoors.
Like all living things, plants must have fresh clean air. On mild days, when the outside temperature is above 65, and during warm rains we put the fire fern, the white jasmine, and the potted yarrow outside for extra sun and fresh air.
"Some slight circulation of air is necessary to check to growth of fungi and mildew," Wilson Bros. advises.
"The main benefit that plants get from fresh air is humidity. It is better to open windows and doors in an adjoining room rather than let a cold draft or sudden gust of air blow directly on your plants."
When the days start to lenthen, diluted fish fertilizer, applied every two or three weeks, appears to benefit the plant.