Providing just the right amount of light for terrariums is the key to successful culture. Newly made terrarium plantings set in moist friable soil, given correct light and a cover to hold in humidity, can go on for days, weeks, months, and yes, even years without water.
The location of the planter will greatly influence just how often water is needed. Naturally, a terrarium placed in a sunny spot will dry out faster than one in filtered light or shade. Indeed, it is never a good practice to place terrariums, other than those planted entirely with cacti and other succulents, in a bright window. The sun creates a steamy jungle like atmosphere inside the terrarium, and covers the plants with beads of moisture. Sun, shining on these, turns them into veritable burning glasses which disfigure the tender foliage. Place all newly planted terrariums in a shaded area, near a northern window, for a week to ten days. When the inside fogs over with condensation, remove the cover for an hour or so to allow the excess moisture to evaporate.
After a new terrarium has full shade for a week to ten days, begin to give it more light. Move it into better light, and wait a few days to see how the plants are doing. If they appear to be losing color and leaning in an ungainly position, move them still closer to strong light. Once the lighting requirements are established, you can move this garden under glass to any similarly lighted spot in your home.
Providing just the right moisture for terrarium grown plants is important, but if you have followed the initial directions and have found a good growing site, watering will be no problem. As with other plantings, too much water encourages rot and too little causes thin leaves to shrivel.
If plantings appear dry, water them with a pitcher or one of the new bottle and tube watering devices. They will benefit also from a mist with a fogger or atomizer filled with clean water. Siphoning water through a small tube makes it easy to add moisture precisely where it is needed in a terrarium. Covered terrariums growing in filtered light seldom need watering more often than once every four to six weeks. Use a half strength solution of fertilizer for every other watering.
If you follow these simple steps, you can enjoy your bottle garden for years to come.
