When you buy seedlings from a nursery you’re paying professional growers for their expertise, the overhead of their facility, and of course the containers, potting mix, and seed – as well as the retailer’s markup. Generally speaking it’s a good deal.
The downside is that you’re stuck with the varieties they select, and if you’re the type of person who enjoys perusing seed catalogs, or growing specialty plants then you probably want to grow from seed.
Professional containers are sold in large quantities – too many for the average person - and used containers must be washed and sterilized in a solution 9 parts water and 1 part bleach for at least 5 minutes. But there’s nothing wrong with using Dixie cups, egg cartons and plastic ice cube trays with holes punched or drilled in the bottom for drainage as long as you know that they all have their limitations.
Potting mixes come in several varieties. My favorite consists of equal parts of peat moss, vermiculite, and pearlite, but you can use a mix of peat, sifted compost, or leaf mulch with sand, and or garden soil. If you use a mix with sphagnum peat be sure to kneed it as you add water until it is thoroughly wet, even squishy. I wet my potting mix with a soluble fertilizer added to the water, the best being Jacks Professional 9-45-15 with micronutrients, but you can also use house plant fertilizer rated 15-30-15 to get your plants growing. Basically plants need more phosphorus at an early age to develop the root system. (Fertilizers are rated with nitrogen first, phosphorus second, and potassium third)
Full spectrum grow lights are pretty expensive and seedlings will do as well with a mix of fluorescent and incandescent bulbs. Closer is better but if you can’t raise or lower your lighting then keep the lights within one to two feet of the plants.
Just as important is the temperature of the potting mix. Roots prefer a temperature of ranging between 68 and 75 degrees. Bottom heating can be accomplished using insulated heating cables buried in moist sand – available at nursery supplies like Hummert International – or rubberized heating pads made for bottom heating seedlings.
Some people put two seeds into every container and pluck the duplicates, but commercial seed is at least 90% viable, and being pro-life I like to give every seed a chance at becoming a plant. Let your conscience be your guide.
A common mistake is over watering and the result is fungal infections. Remember that roots need oxygen, and seedlings don’t need a lot of water to sprout. So wait 5-7 days after planting before the first watering. If you’re bottom heating then once every 3-4 days, if not continue with the 5-7 day routine. As the seedlings progress beyond the seed leaves and begin producing true leaves you’ll want to alternate watering with the feeding of one of the above mentioned fertilizers – about once a week.
Growing from seed offers more than merely selecting your personal preference in plant variety. If you have children it can be a teaching experience. If not you will still have the satisfaction of cultivating your garden from start to finish.