Growing Your Own Hibiscus Sabdariffa Plant
While Hibiscus sabdariffa is a native plant of the tropics, given the right care they are also perfectly capable of being grown and harvested in northern climates with seasonal temperatures. Also known as roselle or sorrel, they are similar to humans in that they thrive best and are healthiest in conditions of moderation. Whether you are dealing with temperature, water, or fertilizer, too much or too little is harmful. Moderation is key, and a healthy hibiscus will produce quality calyxes for consumption.
Be sure to nick the bottom of the seed, the flat part, before planting. If there is no seed meat, it will not grow. If you do not live in a climate that has reasonably predictable spring weather or weather that is too wet, it is best to plant hibiscus seeds in early spring in trays. You can then be in a position to move them indoors if the weather becomes hostile. Wait until they are established enough to not be tipped over by an exceptionally hard rain to plant them in the garden. Tipping can kill a new seedling quickly. It is probably safe to move them outside after they get to be about three inches tall. Seeds will typically germinate between ten days to three weeks after planting. After planting the seeds, keep them lightly watered, enough to keep the soil moist but not wet. Spray them with a mist bottle three or four times per day.
Pot or Garden Planting
If you live in a cooler climate and don't have a greenhouse or an adequate place indoors, you may need to adjust the time of planting described above accordingly to ensure there will be no temperatures that are too cold. Hibiscus sabdariffa can die at temperatures below 40 F or 4 C. If you live in an area with frequent frosts, planting in ground may not be an option. If in doubt, grow your hibiscus in containers.
When planting outside, choose an area that will be in full sunlight. If you live in a consistently warm climate, this is not as critical. In most circumstances, however, they thrive best with as much sunlight as possible. The soil needs to be made to not retain water. If you don't have any well drained soil on your property, you will need to adjust the area where you decide to plant by adding a few inches worth of a combination of sand and peat moss. The ideal ratio should be 2:1:1 of soil, peat moss, and sand, respectively.
Water the soil when it becomes dry to the touch. To reiterate, water only enough to make the soil moist, not wet.
It is critical to use the right type of fertilizer. The fertilizer needs to be one with low phosphorus, moderate nitrogen, and high potassium. Fertilize every two to three weeks. If the leaves are turning brown at the tips, that is a sign they are getting too much nitrogen. That is a warning sign of stress, but don't panic, just prune the bad leaves and adjust your fertilizer frequency. Hidden Valley Hibiscus recommends a 17N - 5P - 24K fertilizer. The most critical aspect of the fertilizer is that the phosphorus content is low. Too much phosphorus can sicken a hibiscus in a matter of a couple weeks.
Apart from freezing temperatures, a grown, established hibiscus usually gives ample notice of stress before it is killed. The usual sign that you are doing something wrong is when the leaves turn yellow. Look at what they may have been getting in excess. Remember how the recent weather has been. The most common reasons for leaves turning yellow are the wrong amount of water, too cold of a temperature, not enough water, or the wrong amount of nutrients. While too much nitrogen will turn leaves brown, most other problems will cause yellow leaves. If they are not getting enough sunlight, you will need to move them. This is a less extensive task if they are potted rather than in ground. If it has been cold lately, pay more attention to the weather forecast, and bring them indoors. If their soil is too wet, cut down on the amount of water.
Harvesting the Calyx
Calyxes are easiest to remove and cut when they are fresh. When they are first fully grown, they can be snapped off of the plant quite easily by hand. If you wait until they harden, then you will probably need to use pruners.