The Basics of Growing Rhodiola in Alaska
Imagine the natural habitat of this perennial sub-arctic plant: at high elevations in northern mountains above the tree line, where the winters are very cold but with lots of intense summer sunshine.
Although it is a succulent and can therefore tolerate dry spells, it grows best where there is at least a little reliable moisture, usually from rivers and streams or on cliffs overhanging a lake or the sea.
If you think your field or garden is cold enough in the winter and mild enough in the summer, Rhodiola rosea should do well. However, you probably live in a more temperate environment than its natural high - latitude habitat, so your field location may favor other local plants. This means that they will likely encroach into your rhodiola field so you will need to plan for weed control. Remember, its niche is to grow where most other plants cannot take hold.
Because Rhodiola rosea naturally grows in relatively poor soils, there aren’t a lot of obvious soil requirements but there are some basic necessities. Soils can be mildly acidic but need to have good drainage and full sun exposure. Although it will grow – albeit slowly - in nutritionally poor soils, we don’t yet know the secret mineral / fertilizer recipe for robust and predictable growth. From reports by Alaska growers, organic matter in the soil is also important, but this is not yet well understood. Basically, Rhodiola rosea is very durable and will grow in many Alaskan locations, but we are still learning how best to grow it as a commercially viable crop.
We are currently working with the University of Alaska through a grant from the USDA to determine best agricultural practices. Stay tuned!
Winter Stratification Method
These seeds are easily germinated in the winter with minimal care. For best results, make sure there are at least two months of cold winter left.
Place 1-2 seeds one half inch apart in moist, well-draining potting soil. Place outside in an area where they will receive sunlight in the spring and summer. Do not allow to dry out - cover with snow if possible. Otherwise cover with plastic, such as cellophane. Trays may be stacked on top of each other.
Seedlings will sprout when the snow begins to melt. They can be planted in the ground when they are at least 3-4 inches tall, either by late fall or the following spring.
Seed treatment with gibberellic acid
This is an alternative method to the winter stratification method.
Rhodiola will readily germinate using Gibberellic acid (GA-3) at 2000 ppm (parts per million =0.2 per cent solution). GA-3 is a natural organic compound, and is a permitted substance in organic production if it is made using a fermentation process. To prepare 2000 pm solution of gibberellic acid for seeding do the following;
- Dissolve 1 gram GA-3 (95% purity) in 500 ml distilled water. GA-3 is difficult to dissolve so it will require prolonged stirring. Prepared solution stored in the dark at room temperature will remain effective for some time.
- Soak Rhodiola seeds for 2 hours. Keep the seeds at room temperature with occasional careful shaking to make sure all seeds are completely covered with the solution.
- Drain and air dry seeds completely. (Use a paper towel to drain and dry the seed) Once dried, seeds are ready for planting.
- Seeds so treated will germinate within 1 week. Ensure the weather outside is warm before taking outside.
- Do not bury the seeds, and cover seeded trays with clear plastic to keep them moist. Do not let the growth media dry out or let it broil in the sun.
Rhodiola rosea grows best in mildly acidic, well draining soil with good sun exposure. Plant at least 1.5 feet apart, as it grows big and bushy to about 18” at maturity. Watering may be necessary during lengthy hot dry summer weather. To promote good root growth, they should be weeded regularly. Plastic mulching works well, especially first 2-3 years. Medicinal maturity is reached the fifth year of growth and roots are best harvested in late summer.