By Melanie Mathieson
The Gardening Guru
By starting seeds indoors, you often can extend your growing season by up to 10 weeks, which can be very beneficial for plants that have a longer “days to maturity” time frame.
You even can start some of the newer hybrid varieties with shorter “days to maturity” time frames indoors, and then sow some directly into the garden so you can have a harvest of produce early and over an extended period of time throughout the summer months.
When starting seeds indoors, you want to determine the last frost date in your area. This is usually June 1 in our area.
This may seem late because sometimes in May we have hot days, but June 1 is the average last frost date for this area as we still can get frost at night after a warm day.
Count back the desired time from this date to determine the time to start your seeds indoors.
If planting annuals, most can be planted six-eight weeks back from the last frost date.
When starting perennials indoors, the seed package usually gives recommendations, but you usually can start them indoors six-eight weeks back from the last frost date.
By doing so, your perennial will not bloom in the first year in the garden, but that is okay as it makes for a stronger plant to survive the winter and flourish the following year.
Just don’t start your plants too early because the temperatures indoors can be a little warm, and the light conditions a little low, and you end up producing weak, pale green, and spindly seedlings.
Plants growing indoors prefer temperatures between 10-16 degrees C instead of the 20-22 degrees C that a home temperature usually is set at.
The ideal place would be a south-facing three-season room, but we do not all have those attached to our homes. As such, you may have to sacrifice a cooler place in order to make a place for the trays with adequate light, like a south-facing window.
In areas where you are short of light, fluorescent lights can be hung above the planting trays. Use a 40-watt, double light fixture with two lights for every four trays of plants you have.
Suspend at a height so all the trays get even exposure, but never closer than 10 inches so there is room for the plants to grow.
There are other grow lights available on the market, as well, but these can be more expensive than a common fluorescent light fixture (choose whichever you prefer, and which fits your needs and budget).
If you have a grow light system, you even can grow plants in your basement or heated garage—and not have to move the trays around to chase the light exposure in the house throughout the day.
A few weeks ago, I gave you tips on some items that make good planting trays. If you already have some mini-greenhouse or other commercial trays, that is fine, too.
Gather all of your potting trays or pots together, and make sure that if they are not new this season that they are thoroughly cleaned and then rinsed in a bleach solution (1/4 cup of bleach per one gallon of warm water) to ensure any traces of moulds and bacteria are gone.
You also can use peat pellets that are condensed disks of peat that expand into a pot once hydrated with water (one seed per peat pot is ideal and makes for easy out planting).
It is important to choose a good potting mix for starting your seeds. There are many good products available today, and go by many brand names, but all you want is a good quality potting mix that has been sterilized.
It is not necessary to have a mix that is fortified with fertilizer because you can add this when you water the seedlings.
If you want to choose a soil-less mix, you can, as well—or make your own. This is a mixture of equal parts of peat moss, vermiculite, and perlite so you also can easily make your own mixture.
During processing, all three of these products have undergone a treatment that includes sterilization. Some of the soil-less mixes also will contain sand instead of vermiculite or perlite, so make sure they have been sterilized.
The soil-less potting mixes do not contain any nutrients so you must add some by fertilizing when you water.
Never use soil from your garden for starting seeds. This soil will start to compact tightly soon after planting, stunting the growth of the seedling, along with the fact this soil will be filled with weed seeds, moulds, and bacteria that will flourish in the growing conditions of the house.
Fill your trays, pots, or planting containers three-quarters full of potting mix, sow the seeds on the surface, and then cover with a light sprinkling of soil.
Water the soil so it is very moist, but not water-logged. And water slowly so as not to wash all the seeds out from under the cover of soil.
To trap the heat and moisture, place the clear plastic lids on the planting trays and containers, making sure you have a tight seal.
If you do not have a clear cover for your container, place it inside a clear plastic bag of choice and seal tightly.
Keep the trays warm until the seeds germinate using some of the tips from last week. Once the seedlings reach the top of the plastic cover, remove and treat like any houseplant until it’s time to put the seedlings outside.
Do not let the soil dry out when the seeds are germinating—even if you have to remove the cover to water. And make sure once you remove the cover permanently, you do not let the seedlings dry out but also do not waterlog them.
Next week will bring you some more tips on how to care for these seedlings and prepare them properly for out planting, so stay tuned.