For spring flowering plants, geranium seeds should be sown in early- to mid-February.
For many years, geraniums have been a common choice for bedding plants. Cuttings are a frequent way to grow plants. Geraniums can, however, also be raised from seeds. Hybrid geraniums that are grown from seeds have great vigor, heat tolerance, disease resistance, and free blooming.
Growing geraniums from seeds is not too difficult. Geranium seedlings, however, develop slowly. For spring flowering plants, geranium seeds should be sown in early- to mid-February. Approximately 13 to 15 weeks after seeding, flowers begin to bloom. Geraniums from the Elite, Orbit, Maverick, and Multibloom Series are recommended for Iowa. A series is a collection of closely related types that share similar traits like height, spread, and flowering behavior. The only trait that typically varies within a series is the color of the flowers.
Jiffy Mix and Redi-earth are two great soilless mixtures that work well as germination media. Geranium seedling damping-off can be a significant issue during germination. Different species of fungi attack the seedlings and kill them, which is what causes damping-off. Containers used to start seeds should be spotless and have sufficient drainage to deter this. Prior to disinfection, previously used containers should be cleaned in soapy water and dipped into a solution of one part chlorine bleach to nine parts water.
The germination media should be poured into the container to within 1/2 to 1 inch of the top. Lightly firm the medium, completely wet it, and then give it some time to drain. Rows of seeds should be 2 to 3 inches apart, and the medium should cover the seeds by about 1/8 inch. After planting, thoroughly hydrate the soil by immersing the container in water only partially. Remove the container from the water after the surface is damp, then let it drain. The media can alternatively be hydrated with a gentle water spray from a sprinkler made of a rubber bulb or a similar tool.
Use clear plastic food wrap or a clear plastic dome to cover the container to maintain a constant moisture level during the germination process. Place the container in a well-lit area away from the sun. If the covered container is placed in the direct sun, there could be an excessive accumulation of heat. When germination is taking place, the medium’s temperature should be between 70 and 75 degrees F. The seeds should start to sprout in seven to ten days at the right temperature and moisture content.
As soon as the seeds start to germinate, remove the plastic covering. Put the seedlings in a window with natural light or under a light fixture. Fluorescent lights should be turned on for 12 to 16 hours a day and placed no higher than 4 to 6 inches above the seedlings. When the seedlings develop their first true set of leaves, transplant them into separate containers using a well-drained commercial potting mix. Handle the little seedlings by their leaves since the fragile, delicate stems are easy to break. When transplanting, place seedlings at the base of the seed leaves (cotyledons).
Grow seedlings under fluorescent lights for the greatest outcomes. One 40-watt cool white and one 40-watt warm white fluorescent tube can be used in a conventional fluorescent shop light. Due to little light, plants grown in windows frequently grow tall and spindly. Geraniums prefer daytime temperatures of 70 to 75 degrees and nighttime temperatures of 60 to 65 degrees. When the soil surface is completely dry to the touch, water the geraniums thoroughly. Fertilization is probably not required if using a potting mix that is sold commercially and has a slow-release fertilizer. For potting mixes without a slow-release fertilizer, applying a diluted fertilizer solution once every two weeks should be adequate.
Before putting the plants in the garden, harden or acclimatize them to the outdoors for seven to 10 days. First, plant the geraniums in a sheltered, shaded area. Then progressively subject the plants to extended sun exposure times. When there is no longer a chance of a frost, plant the geraniums outside. Early May is typically a good time to grow geraniums outside in central Iowa.
How do I gather geranium seeds?
Geraniums feature a spring-loaded seed distribution system, which means that as soon as the seed is ready, it is pinged away from the plant for up to three meters, making seed collection from these plants challenging.
The fact that many current cultivars are sterile and hence don’t generate any seed further complicates matters. Typically, garden centers with non-Latin marketing names will sell these.
So, if you wish to collect seeds from a geranium, you must first carefully examine the “seed heads” and check to see if there are five hard, bulging pods at the base of the primary flower spike. If so, the following visual cues indicate the ideal time to collect the seed:
The far left pair should be left alone until both the central spike and the seed casings at its base start to darken because they are still too green. Black spike and dark seed pods, which are in the middle, are ideal. The seed has been released, the two on the right are too late, and you can still make out the ruins of one of the springs.
These are geranium pratense seeds, however viable geranium plants of any variety will yield the same results.
I gather them by delicately wrapping my palm around a pair of ripe seedheads (they usually grow in pairs) and cutting with scissors. By pulling, there is a chance that the plant will scatter its seeds. After that, put the seedheads in a paper bag and let them ping for about a week on their own. If seeds are placed right away, they may sprout rapidly. If not, it may take a cold snap to induce them to sprout, so place a seed tray somewhere that will get some frost without getting too wet.