As our nursery crews finish lifting and packing seedlings, ArborGen orchard staff have been hard at work testing seed, a key component to making sure we have what our customers need when and where they need it. Seed testing involves four metrics: moisture content, purity, seed per pound, and germination.
One of these tests, germination, begins with the sample seed being soaked in water overnight, then kept in the cooler for 30 days, a process known as stratification. Stratification causes the seeds’ embryos to begin cellular activity leading to germination. The seeds are then surface dried before being placed in germination dishes containing moist germination media. Precision placement occurs with the help of a handheld vacuum with 100 small holes, allowing for even distribution in the germination dishes. For germination testing we sow four replicates of 100 seed per germ dish, then count germinants every 7 days for 28 days.
Once testing is complete, seed is “allocated” to each of our six nurseries – this year we have allocated 26,000 pounds of seed. The results of the seed tests are used by our nursery staff to determine how much seed to sow per foot of nursery bed. A difference of 1% in germination rate can cause our crop to go up or down by 3,000,000 seedlings! Accurate seed placement with our precision sowers using these test data ensures the highest seedling quality possible for our customers.