Something that was missing in the presentation was ventilation. Air circulation is necessary to prevent mold buildup, which can kill young seedlings. Large greenhouses use fans, or forced air. At home, if seeds are started in an enclosed space or an area with poor circulation (such as a basement) a fan may be needed. If using lights or heat mats, their heat can be utilized for convective circulation, provided pathways are allowed for air flow. I had a lighted shelf which was against the wall, and had problems with mold. Moving the shelf several inches from the wall allowed convection from below, which corrected the problem.
The plant movement caused by a fan also simulates wind, which helps to strengthen & thicken stems, and leads to stronger transplants. You can get the same stimulation by carefully but roughly caressing the plants once or twice a day; I've done that, with good results. It leads to shorter, stockier transplants... and depending upon what you grow, can make your hands smell interesting.
The BC method of planting multiple seeds in cells is the same procedure I use... and is the easiest method for gardeners, provided that there is enough seed. Like BC, everything I grow is OP & from saved seed, so seed quantity is seldom an issue. If starting expensive hybrid seed though (or something rare), where you start with a limited quantity of seed, you would probably use only one seed per cell. In that case, it is less important that every cell be filled, than it is for every seed which sprouts to be used.
And finally, I can't help noticing that nowhere in the presentation did he use the word "dibble".
I really wish I had a large, heated greenhouse, it would greatly simplify my seed starting. Unfortunately, when I inquired about building one, my local township told me that I can't erect another structure on my property due to zoning limitations. Based upon my frontage, I'm "maxed out" on my utility square footage... so I could only build a greenhouse if I tore something else down.
Zoning based only upon frontage completely overlooks the fact that my L-shaped lot is 66' wider on the back 2/3 of the property, which is effectively another lot. A structure is considered "permanent" if it has a foundation, or if wiring or piping is permanently installed. My small Harbor Freight greenhouse is permitted, since it is not mounted on a foundation & has no permanent wiring or heating... but it gets pretty crowded if weather prevents me from moving the larger plants outside.
At present, due to the large numbers of transplants I use every year, it is a juggling match. Seeds which require heat to germinate (peppers, eggplant, Moringa, water spinach, limas, some gourds) are started in a collapsible green house, with a thermostatically-controlled heater. Once germinated, they are moved to the lighted room-temperature growing area, where they will stay until the solar greenhouse has become warm enough. As planting time gets closer, other waves of transplants (beans, cowpeas, squash, cucumbers) will be started under the lights; weather permitting, those are moved outdoors into sunlight as soon as they germinate. Then I'm just hoping that we get a dry Spring, so I can get the plants into the ground before they outgrow their pots.
