How To Grow Iris From Seeds
There is nothing as exciting as growing your own iris seedlings; whether they are from crosses you have made, someone else has made, or a bee has made. Every time a seedling blooms for the first time - - it's like Christmas! And really, it is SO simple. Iris seeds can be planted at any time, but the best time to plant the seeds is during the fall/winter/ and VERY early spring months.
First, soak the seeds in water (using a pudding bowl, cup, or similar) for at least 48 hours up to 2 weeks. Change the water out daily using a strainer to catch the seeds (so as not to lose any). No nicking is necessary. Soaking will cause these shriveled up seeds to plump up as well as to remove the inhibiting factors within the seed so they will germinate more easily.
I've found it best to plant the seeds into either window planter boxes, or one gallon containers using a mixture of potting soil and Jiffy *seed* soil mix. (Or any other brand of seed soil/ or germinating mix). Apply more of the Jiffy *seed soil mix* at the top of the pot, window box, or container. Next, plant the seeds about a half inch deep and preferably at least a half inch apart. In a regular 'one gallon container' plant no more than 20-25 seeds.
Some people prefer to sow the seeds directly into the ground in the fall/winter, and let the natural cold of winter and nature itself wash the inhibitor factors out of the seed. And that will work too. Due to the fact that some varieties of seeds NEED several weeks of cold weather outdoors to germinate, makes it advisable NOT to plant them in late spring/early summer or summer months. Not to confuse you, but I've also found that some seeds which have resulted from crosses made with reblooming irises do NOT need the cold winter chill factor in order to germinate.
After the seeds have been planted ** Keep the soil moist, (not wet) at all times/never drying out ~ to insure germination. If they dry out for too long or too often -- germination will be poor. Then you'll need to wait until the following spring to see those seeds germinate. Some years 55-75% of the seeds germinate, other years close to 80%-100% using this soaking method and keeping them continuously moist after planting. Without soaking the seeds first and keeping them moist at all times, germination can be far less – down to 25% - 45%. However by the second year, come spring, germination will be greatly improved. Most of the seeds retain the capability to germinate in following years if they haven’t all germinated within those first 2 years. Personally, I've never waited longer than those first 2 years, but I have dumped the used soil in tree wells containing ungerminated seeds only to discover them germinating years later.
NOTE: Iris seeds will germinate for up to 18 years. That is how they survive in the wild. So, if you want to wait & save some of your seeds for next year or the year after to plant - - it‘s not a problem with IRIS seeds. I've saved seeds in sealed envelopes for up to 4 years and they have all germinated just fine for me. Once planted in the fall or winter - germination of the seeds will take place the following spring. (Usually anywhere from 4 weeks to 12 weeks after planted and set outdoors).
Depending on climatic and growing conditions the seedlings (once sprouted) can produce "maiden bloom" for the first time in the spring of the following year, if not then surely by the next spring. Commonly warmer climates will see "maiden bloom" the first spring after they have sprouted; in cooler climates usually 2 years after they have sprouted.
I hope many of you decide to try your hand at growing irises from seed. And I hope these instructions prove to be helpful to you. Now - good luck with those iris seeds! It should be exciting to see what you get.
Margie Valenzuela
TAIS Board Member and Hybridizer
Oro Valley, AZ