Garden Seeds – Tips on Growing Alyssum From Seed

Stage 1 Radicle (Embryonic Root)

Time of emergence 2-5 days

• Soil Temperature should be 78-80ºF (25-26ºC).
• Keep media moist and close to saturation by watering before placement of seed.
• Do not cover or bury the seed, as light is necessary for germination until radicle emergence.
• The germination temperature at this stage should be 72 to 75ºF (22 to 24ºC).
• Light levels at 100 to 400 fc (foot candles) will enhance the germination process.
• Soil pH should be 5.5 to 5.8 with soluble salts less than (EC 0.75 ). Alyssum is sensitive to high salts especially ammonium during this process of germination). It is very important to keep your ammonium levels less than 10 ppm.( parts per million) 

Stage 2 Hypocotyl (Stem and cotyledon emergence)

Time of emergence 7-10 days.

• First start reducing moisture levels once the radicle emergence occurs. At this point allow the soil to dry out slightly before watering again, this will aid in the germination and rooting process.
• The soil temperature at this point should be 78-80ºF (25-26ºC).
• The soil pH should be at 5.5 to 5.8 with soluble salts less than ( EC 0.75). Also keep the levels of ammonium less than 10 ppm.
• You can start fertilizing once cotyledons are fully expanded with 50-75 ppm.N from a nitrate feed of 14-0-14, that is a calcium/potassium base.
• A good tip would be to also apply a protective fungicide for damping off organisms once full stand is achieved.
• You should alternate watering with clear water then with fertilizer. Another important issue is when you should water- do so early in the day as the foliage has time to dry by the night time as to prevent diseases. 

Stage 3 Cotyledon (Growth and development of true leaves)

Timing of this growth 14-21 days.

• Maintain the soil pH at 5.5 to 5.8 with the soluble salts less than ( EC 1.00)
• You can increase the feed at this point to 100-150 ppm N- using a 20-10-20, and alternating with a 14-0-14 or other calcium/potassium fertilizer.
• It is important to alternate your fertilizing feed schedule with every 2 -3 clear water irrigations. Do not allow plants to wilt, as this will cause drought stress and burn the leaves
• The soil temperature should be between 65-68ºF (18-20ºC).
• Keep light levels less than 2500 fc, if higher you will have yellowing or burned foliage. This will help in the production of producing a well branched plant.
• Alyssum are very sensitive to high salts so do not overfeed.

Stage 4 Getting ready for transplant/growing on period

• Do allow the soil to dry thoroughly between irrigations, however do not to allow the plants to wilt.
• Keep your temperatures maintained for Days at 60-62ºF (16-17ºC) and for nights at 50-55ºF (10-14ºC)
• Maintain the soil pH at 5.5 to 5.8 with the soluble salts less than ( EC 1.00)
• You can continue to fertilize at a feed level at 100 to 150ppm N with a 14-0-14 fertilizer as needed, however the pH and the EC must be maintained as stated.
• Alyssum requires full sun as a finished plant for the outdoors. They will also tolerate some partial shade.

USDA Hardiness Zone -First Frost Date- Last Frost Date

• Zone 1 -July 15th -June 15th
• Zone 2 -August 15th- May 15th
• Zone 3 -September 15th May 15th
• Zone 4 -September 15th May 15th
• Zone 5 -October 15th April 15th
• Zone 6 -October 15th April 15th
• Zone 7 -October 15th April 15th
• Zone 8 -November 15th March 15th
• Zone 9 -December 15th February 15th
• Zone 10 -December 15th January 31st (sometimes earlier)
• Zone 11 _No frost. No frost.

Terms and their meaning: EC=Electrical Conductivity

Plant injury resulting from excessive soluble salts may first occur as a mild chlorosis of the foliage, later progressing to a necrosis of leaf tips and margins. This type of injury is largely attributed to the mobility of soluble salts within the plant. As these salts are rapidly translocated throughout the plant, they accumulate at the leaf tips and margins. Once the salts reach a toxic level they cause the characteristic "burn" associated with excessive salts. For an accurate reading get an EC meter. Soluble salts in irrigation water are measured in terms of electrical conductivity (EC). The higher the salt content the greater the EC. In general EC values exceeding 2.0 are considered toxic to plant growth. Monitor your water quality frequently in order to avoid potential problems from soluble salts.

FC=Foot Candles

 Light intensity is a primary factor in the photosynthesis of all plants. Full unobstructed sunlight has an intensity of about 10,000 fc. Where as an overcast day will produce an intensity of around 1,000 fc. A window sill or light around a window or patio glass door can range from 100 to 5,000 depending of course what direction the light source is facing, or the time of year and your latitude.

PPM=Parts Per Million This unit of measure is relatively unique to the greenhouse industry and often there is some confusion on how ppm is calculated. I. To calculate the ppm contained in 1 ounce of material first solve for B: A x 75 = B  A = the % active ingredient (AI) in the fertilizer B = ppm contained in 1 ounce of the material in 100 gallons of water  Example: Calcium nitrate contains 15% N (0.15 x 75 = 11.25). If 1 ounce of calcium nitrate is dissolved in 100 gallons of water the solution will contain a II. To calculate the number of ounces of material required to make up a desired ppm concentration solve for C:  C = Desired ppm conc. / B B = ppm contained in 1 ounce of the material in 100 gallons of water (from above). C = number of ounces of material to add to 100 gallons of water to achieve the desired concentration.  Example: To make up a 250 ppm solution of calcium nitrate first multiply the AI x 75 (.15 x 75 = 11.25). Next divide the desired concentration by 11.25 (250/11.25 = 22). To make up a 250 ppm solution of calcium nitrate you would add 22 ounces to 100 gallons of water. aproximately 11.25 ppm N.