I greatly prefer *hand cleaned* seed. Seed which I have grown and gathered myself has been hand cleaned. Seed produced by some commercial growers has been *machine cleaned*. You'll know machine cleaned seed if you see it, because it contains a lot of chaff in addition to the seed. (They basically grind up part or all of the plant to obtain the seed.) I recommend a modified method for growing machine cleaned seed. The following discussion is only for hand cleaned seed.
Seeds of bush mimulus are best started in October or November, but they may be started any time, especially October through March. No special preparation is needed for bush mimulus seed. They are easy when certain precautions are taken.
I start my seeds indoors (in the kitchen), and grow them at room temperature. I *do not* use bottom heat. Bush mimulus seeds are very small and should be sprinkled on the media surface. I *do not* cover the seed media in any way. As soon as the seedlings emerge, I move the seed tray outdoors. Note: conditions which are too warm, or too humid may encourage growth of mold or fungus on the media. That could kill the emerging seedlings. If mold forms on the media, try using a fine water mist to discourage it, or place the seedling tray outside overnight. Warmer conditions will encourage faster germination, but will also encourage legginess of the seedlings, as well as damping off.
The best way by far to start bush mimulus seeds is with Parks Seed Starts. This is a plastic holder block with 18 small peat pellets in it. Outstanding results have been obtained with this media. No other method I am aware of produces results as good. (If you do use a different media, it should be sterile to discourage fungus growth.)
Because there are 18 compartments in a Park Seed Start block, I try to distribute my seed between the compartments, 1 to 3 seeds for each compartment. (Sometimes I slip and more seed than that goes into a compartment.)
Following the manufacturer's directions, I soak the Park Seed Starts seedling block in a moderate size tray of water (which has some of the provided fertilizer in it -- half strength). I soak it for at least a half an hour, or longer if needed, until the media is thoroughly moist. (Out of the box, the media will be somewhat moist, but must still be soaked. Wrap unused seedling blocks in provided plastic wrap and tape it. Try to keep media blocks moist in storage, but they will gradually dry out nevertheless and must be soaked longer when used.)
Meanwhile, using a weatherproof marking pen, I write a code number on each end of the small provided tray that comes with the Seed Starts kit. I also record that number in my computer file and/ or my records notebook, along with information about the seed variety I am going to start, and the date.
After soaking, I move the plastic block to its provided tray. (Left over fertilizer water can be donated to plants around the garden or house.) I carefully sprinkle a few seeds (preferably 1 to 3) into each compartment of the media. Good light will help you to see what you are doing. (The best way I know to do this is to have the seeds in a small glassine envelope, and carefully pour them out of it. Or, half of a gelatin capsul, #0 or #00, may be used to hold and pour the seed.) Next I sprinkle a fine water mist over each compartment in the seed block with my handy water mister. (This settles the seed against the media.) Now, move the seed with its provided tray to its location, and fill the tray to the brim with water. Keep water in the tray at all times -- you'll probably need to fill it about twice a day, as the furnished tray is quite shallow.
*Germination* usually takes about 5 to 7 days, or sometimes as long as 8 weeks for older seed or unusual conditions. As soon as the seedlings emerge, move the tray to outside. Failure to place outside in adequate light will cause the seedlings to be skinny. Constant moisture is a requirement during germination and the first month thereafter. Occasionally, delayed germination will be noted. It would appear that when a few seedlings are growing in a confined area this may supress other seed germination; however, if those seedlings die off, then the other seeds may germinate (delayed germination).
Seedlings can be very small when they first emerge, and should be fertililzed twice a week with a half strength solution of liquid fertlizer. The fertilizer provided with Parks Seed Starts works just fine. Another brand of fertilizer I have used with equal success is "Eleanor's VF-11". I mix up a the diluted fertilizer-water in a quart bottle, and save the unused portion for next time. Fertilizing in this way will encourage the seedlings to grow quickly to a more manageable and sturdy size.
*Protect* young seedlings from heavy rain, hail, and snails. They do not need protection from mild frost. If it is very windy be certain seed media does not dry out, and that the seed blocks do not *blow away*, as they are quite light. Thin to one plant per compartment when 4-8 leaves develope. You can also try growing plants without thinning. Transplant in 1 - 3 months to 3 or 4 inch pots. Seedlings grow much faster when transplanted this way. (Park Seed Starts are very easy to transplant -- just push out the peat plug from the bottom with a pencil.) The depth of the transplant pot is more important than the width. I have had good results using 4 inch pots, and comparable results using special 2 1/2" pots which are 3 1/2" deep (these save space). I use 'Supersoil' planting mix for all pot grown plants. Some other brands of planting mix are *not as good*. For best results bush mimulus should be transplanted a second time after the plants are at least 3/4" to an inch high. They may be moved to black plastic 'nursery cans' of a gallon size (or larger), or planted in open ground. If bush mimulus are to go into the garden, they should be nursed along in 4 inch pots first until fairly large. I use a small amount of 'Osmocote' time release fertilizer (pellets) in the planting soil for all pots -- perhaps 1/4 teaspoon for small pots, and 1 teaspoon for 1 gallon or larger pots. This fertilizes the plant for up to a year.
Some of the smaller varieties, particularly m. aridus, are comfortable living in 4 inch pots permanently, although the plants will not grow as large as they would in gallon cans or open ground. Other varieties, such as m. longiflorus, may be somewhat cramped growing in gallon cans, and would do better in 2 gallon cans or open ground. (One commercial grower even uses 5 gallon cans for some of the larger hybrid varieties.)
*Viability* of bush mimulus seed is good for 2 or 3 years. Best results are obtained with very fresh seed, harvested a few weeks before it is grown. Germination speed and seedling vigor decline as the seed ages. Five year old seed has been successfully grown. For longer storage, seed should be stored in the refrigerator or frezer. Seed 16 years old which had been stored in freezer by SABG was successfully grown.
[updated 10/21/2001]