HIBISCUS

Production - general information, soil, planting, timeline

Soil
Use a well drained, sterilized planting medium - pH of 5.5 to 6.0. Many growers use a sphagnum peat-based soil.

Planting: fungicide
Unpack the cuttings and provide with water if needed. Plant as soon as possible in the final container. A fungicide drench within one week of planting provides additional protection for the young plant.

Timeline of growing
1. Week 1 and 2 after potting, the maximum EC is 1.0.
2. Week 3, roots are at the side of the pot (70 degrees F) pinch leaving 5 to 6 nodes
3. Week 4, new shoots or breaks are visible, then increase EC from 1.5 to 2.5 depending on light levels and plant needs
4. Finish at an average EC of 1.5
5. Important note: Lower light level means feeding at a lower rate. Anticipating higher light levels allows to preemptively feed at a higher rate. In the winter use mostly nitrate nitrogen. In the spring (higher light and temperature) nitrogen can be composed of mostly nitrate nitrogen with low levels of urea and ammonium nitrate. A high level of urea can cause stress and a high level of ammonium can lower pH.

Production - fertilization, temperature and humidity, light conditions

Fertilizer and pH
1. Many growers sub irrigate the hibiscus crop. Tube or hand watering can also be used.
2. Total salts can range from an EC of 1.5 to 2.5 finishing at 1.5.
3. Feed with equal amounts of nitrogen, calcium and phosphorus, adding more potassium during the last quarter of the crop time.
a. N:K = 2:1 during the 1st quarter of the pot culture (max. EC = 1.0)
b. N:K = 2-3:1 during the 2nd and 3rd quarters of the pot culture 
(EC = from 1.5 to 2.5)
c. N:K = 1:2 during the final quarter of the pot culture (finish at 1.5 average EC)
4. Iron is very important to hibiscus growing. Iron chelate can be added at the rate of 4 oz. per 100 gallons of water. Iron deficiency is visible as chlorotic upper leaves.
5. Magnesium can be used at the rate of 20-35 ppm during the whole crop.
6. A high pH (6.5 - 7.5) can tie up iron and magnesium. Keep pH between 5.0 and 6.0.

Temperature and humidity
Ideal growing conditions range from 70 to 80 degrees F. during the day and 68 to 70 degrees F. at night. Temperature is a factor in producing quality hibiscus. Lower temperatures can extend crop time and compromise plant quality. Humidity can range from 60 to 85 percent. Ideally, average day - night temperatures should be a minimum of 68 to 70 degrees F.

Light conditions
Grow hibiscus with a maximum amount of available light. Year-round production of hibiscus can require shading when growing under high light and temperature.

Production - flowering, spacing, disease prevention, growth regulators, varieties

Flowering - photo period requirements
Hibiscus will flower under natural day-length conditions unless temperature and light levels are low. HID lights can be added if low light conditions persist. However, supplemental lighting is not needed for photo period requirements.

Spacing requirements
Spacing can be done after the last pinch. It allows more air movement and helps prevent fungal and stretching problems. Plant quality is maintained and enhanced by proper spacing.

Pest and disease prevention
Thrips, mite, aphid and whitefly are potential pests. Use chemicals recommended by your local insecticide supplier.  A fungicide spray in combination with an insecticide spray can be effective.

Growth regulators
The Sunny Cities® series can be grown without any growth regulators. Cycocel as a spray can be used to tone and promote even bud-setting. Rate is 250 - 500 ppm (approx. 1/4 - 1/2 oz. per 1 gallon water).

Successful growth is achieved with good light levels, avg. day - night temperature of 70 degrees F., a pH of 5.0 - 6.0 and good fertilization practices.

Production - finishing options & pot sizes

1) 4" pot
1 plant per pot. Pinch leaving 6 nodes which gives 4 to 6 branches. After pinching do not give excessive light until breaks are 1" long - shade may be necessary. In Holland 4" are grown to a max. of 3.5 per  square foot. Some spacing may enhance quality depending on light levels and finish pricing. Crop time is approx. 12 weeks.

2) 5" pot
1 plant per 72 or 102 cell single pinch, or 2 plants per 50 cell with single pinch. Pinch leaving 6 nodes which gives 4 to 6 branches. After pinching do not give excessive light until breaks are 1" long - shade may be necessary. In Holland 5" are grown to a max. of 1.8 per 1 square foot  which is approx. 2 per square foot. Some spacing may enhance quality depending on light levels and finish pricing. Crop time is approx. 12 weeks.

3) 6" - 6,5" pot
1 plant per 72 or 102 cell with 2 pinches, or 2 plants per 50 cell with 1 or 2 pinches. First pinch occurs 2 weeks after potting, leaving 5 to 6 nodes. Second pinch occurs 3 to 4 weeks after the 1st pinch, leaving 2 to 3 nodes. Crop time is approx. 15 to 17 weeks (with 2 pinches).

4) 7" - 8" bush or pot
1 plant per 72 or 102 cell with 3 pinches, or 2 plants per 50 cell with 2 or 3 pinches. First pinch occurs 2 weeks after potting, leaving 6 nodes. Second pinch occurs 4 weeks after 1st pinch, leaving 3 nodes (can be 3 weeks). The 3rd pinch occurs 4 weeks after 2nd pinch, leaving 3 nodes (3 weeks?). Crop time 16 to 18 weeks (with 3 pinches). Spacing is 9 to 10 per square meter or 1 per square foot.

5) 7" tree
1 plant per 72 or 102 cell with 4 pinches, or one 50 cell liner with 3 or 4 pinches. First pinch occurs at 21" in height. Stake each pot. Second pinch occurs 3 to 4 weeks after 1st pinch, leaving 3 nodes. Third pinch occurs 3 to 4 weeks after 2nd pinch, leaving 3 nodes. At this point strip all bottom leaves from soil level up to first pinch. Fourth pinch occurs 3 to 4 weeks after 3rd pinch, leaving 3 nodes. Finish time is 8 to 10 weeks from last pinch. Total time - approx. 24 weeks (with 4 pinches).

6) 10" bush or pot
3 plants from 72 or 102 cell per pot with 3 pinches, or 3 to 50 cell liners with 2 or 3 pinches. First pinch occurs 2 weeks after potting, leaving 5 to 6 nodes. Second pinch occurs 3 to 4 weeks after the 1st pinch, leaving 3 nodes. Third pinch occurs 3 to 4 weeks after the second pinch, leaving 3 nodes. Finish time 20 to 22 weeks with 3 pinches. Spacing is 0.5 per square foot.

7) 18" - 20" bush or pot
3 cuttings from 72 or 102 cell per pot with 5 pinches, or 3 to 50 cell liners with 4 to 5 pinches. First pinch occurs 2 weeks after potting, leaving 5 to 6 nodes. Second pinch occurs 3 to 4 weeks after the first pinch, leaving 3 nodes. Third pinch occurs 3 to 4 weeks after the second pinch, leaving 3 nodes. Fourth pinch occurs 3 to 4 weeks after the third pinch, leaving 3 nodes. Fifth pinch occurs 3 to 4 weeks after the fourth pinch. Flowering occurs 8 weeks after last pinch. Total time - approx. 24 to 28 weeks (with 5 pinches). Spacing is approx. 2 pots per 10 square foot.