What to do when the seeds sprout.
Whenever you observe a seed sprouting, remove it with tweezers and place it in a sterilizing solution to help control damping off. Damping off is caused by fungi that kill young seedlings at the soil level. There is a problem in recommending a commercial fungicide solution for home use. Commercial growers and those that have a greenhouse detached from their living quarters often use a Captan solution which can be prepared by adding 1/4 tsp Captan (1/2 tsp of 50% Captan) to 1 pint of water. Note that Captan has been shown to cause cancer in mice plus other health problems and therefore is not recommended for use in your living quarters. A safer alternative in your living quarters is to dip the sprout in a commercial 3 % hydrogen peroxide solution. After a minute or so remove the sprout from the hydrogen peroxide solution and dip it in a container of water (or in a solution prepared by adding 5 ml of the 3 % hydrogen peroxide to every 95 ml of water). Next, transfer the sprouted seed to a peat pot or a clean seed tray that contains a fine, sterile, soil less commercial seed starting mix that has been lightly dampened with a solution prepared by adding 5 ml of 3 % drugstore type hydrogen peroxide to every 95 ml of water. Use an H2O2/water mixture each time you water until the seedlings are past the damping off stage (normally after several sets of true leaves have formed). The commercial seed starting mix normally consists of a mixture of a number of the following components: sphagnum moss, coir, perlite, a pH stabilizer, vermiculite, sand, water absorbing polymer crystals, and a wetting agent. Most seed starting articles recommend that it should not contain any fertilizer.
What type of water to use? If you suspect that your home tap water is unsatisfactory for growing seedlings (basic, too acidic, high chlorine content, high ion content), you may want to use commercial distilled water, water from your outside garden house outlet (if you have well water and the garden hose outlet provides untreated water) or rainwater that was collected in a clean container.
The seed should be placed with the emerging root in the mix. Next cover the surface of the mix with ordinary children's play sand to discourage Fungus gnats. The sand also serves as an inexpensive "moisture indicator" as the color of wet sand is quite different from the color of dry sand.
A label can be made from a thin piece of cut up plastic (I like to use clear plastic so that I do not block off much light). I use a fine tip black paint marking pen ( the color from ink marking pens can be bleached by the hydrogen peroxide solution. Consider the label as temporary and replace with a larger, more sturdy one when transplanting outdoors.
If you use small 1-3/4 inch square peat pots, you will be able to fit 50 into a standard 11 inch by 22 inch seed tray. If you use 1 1/2 plastic inserts you will be able to fit 72 into the standard tray. Place a layer of sand and "fine grade" water absorbing polymer "crystals" on the bottom of the tray, and place the pots on top of the sand-water polymer mixture. After the initial watering, remove one of the pots and pour the 5 ml H2O2/95 ml water mixture directly on the sand-water polymer mixture. The seedling pots will then absorb the water from the bottom up. This will also help in avoiding damping off of the seedlings. Another reason for the bottom layer is that if one of the seedlings happens to send its roots out the bottom of the pot; the roots will be kept alive by the moist bottom layer. Cover each tray with one of the commercially available clear plastic domes (at least for the first couple of days). Position four of the seed trays with covers side-by-side and illuminate with 2 commercial florescent light, 4 foot "shop light" type fixtures (each fixture holds two 40 watt florescent bulbs). The lights should be kept on 24 hours a day so that the seedlings grow through the critical "damping off" susceptible stage as rapidly as possible. The florescent bulbs can be either the specialty plant grow bulbs or regular "cool white" bulbs. Try to keep the soil mix temperature at 65F to 80F. If the room temperature is below this range, bottom heat can be provided by using a thermostated heating tape or pad (commercially available in garden catalogues).
The sprouted seeds will first produce two "seed leaves", called cotyledons, then their "true leaves". After at least the second set of true leaves appear, the seedling should be transplanted into a larger growing medium such as a 3-inch peat pot (preferably the deep form) or a larger deep plastic pot where the seedling will grow until it is transplanted outside (this last season I skipped the step in the above paragraph and instead put the germinated seedlings directly in plastic tapered 2 inch diameter 4 inch deep plug trays that held 32 cells in a standard tray). The mix for which ever type of container that you select can be similar to the seed starting mix (for convenience a low dosage of organic fish/kelp type fertilizer can be used). I now use Pro-Mix Ultimate Organic Mix with endomycorrhizae inoculant to help develop a strong root system before the first winter.
If the seedling was initially in a peat pot, the pot and all can be transferred into the larger pot. This method minimizes the danger of damaging the delicate root system. If the seedling was not in a peat pot, use a spoon or a flat metal tool to transfer the seedling and as much of the surrounding mix as possible to the larger seedling container.
The larger seedling pots can be placed into a clear plastic clothes storage box. These boxes are available in a number of different sizes. I will discuss here a size (39 inches by 16.4 inches by 9.2 inches height) that is convenient to use with two 4 foot florescent shop light fixtures. This size box will hold (as an example) 44 of the three inch peat pots. As you did for the seed trays, put a layer of sand/water polymer (but here you can use the larger size or "coarse" water polymer "crystals") in the bottom of the box; and then put the seedling pots on this layer. Add additional sand or potting soil to the empty spaces between the pots and the plastic walls of the box. Two sets of double light 4 foot florescent shop lights with 40 watt bulbs will adequately illuminate this size of storage box. Particularly due to the fact that my sunroom does not have a central heating system, I prefer to leave the lights on continuously (night is when the heat from the fixtures is needed the most). In addition, the intensity of florescent light, even when the leaves are close to the bulb, is low enough that for practical purposes a period of night rest is not needed. Of course, a timer can be used to provide an "off" period if desired. The plants can be bottom watered by running water down the plastic sides of the containers into the sand/water polymer layer. It is easy to see the level of the water through the clear box sides. If the florescent lights are suspended by chains, they can be easily raised to always be an inch or so above the growing seedlings. If you are interested in early flowering, use the warm white or plant grow light florescent bulbs rather than the more common cool white.
Once the germination of a particular cross starts it can continue for a year or more, but most of the seeds will normally germinate in one to four months, probably peaking at six to eight weeks. The per cent of the rose seeds from a given cross that germinate is normally unpredictable even for the same cross from year to year. In some lucky cases you may have near 100 per cent germination; in other cases none of the seeds may germinate. Seeds which do not sprout by late spring can be made to become dormant by placing where the temperature will be above 80 degrees Fahrenheit and by letting them partially dry out. Then at the start of the next germinating season, soak the older partially dried seeds for 24 hours in water and place them in a refrigerator at about 40 degrees Fahrenheit for about 2 months to remove the "high temperature secondary dormancy".
For important crosses that have not germinated, I recommend that you keep the seeds for a number of years (as long as they appear healthy - a dead seed will decompose). I have a screened in box in the yard where I place lower priority seeds that are over 2 years old. The screening is complete - top and bottom to keep "critters" from eating the seeds.
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