I don’t start too many vegetable plants indoors. That’s because houses are great for humans but are very unnatural for vegetables, herbs and annual flowers. Most homes are too dark, dry and hot. As a rule flower and vegetable plants do better if they are started in a greenhouse, cold frame or in a hot bed. The only plants that I do start indoors are geraniums, tomatoes, green peppers and sometimes melons.
Here in northwestern Pennsylvania we have a fairly short growing season. There will be another 4 or 5 weeks before cold sensitive fruits and vegetables like tomatoes, peppers, cucumbers or cantaloupe can be safely planted in the garden.
It never makes good sense to start bedding plants early.
Seedlings that are started too early can be subject to damping off and are often leggy and unhealthy by the time they are set in the garden. Pumpkins especially shouldn’t be planted until the weather is downright hot! Early planted pumpkins never do as well as late planted pumpkins.
It’s better to direct sow seeds into a garden a little later rather than set unhealthy bedding plants in a garden too early.
I’m an old school gardener and subscribe to “planting by the signs”. I always try to pick a favorable day for sowing seeds if possible. If you are interested in moon sign gardening, any good current geocentric almanac will have tables or charts for the moon’s phase and position in the zodiac for any given day with some basic information.
When I start seeds without the benefit of a hot bed or cold frame, I usually will use egg-shell seeding pots, peat pellets, peat pots or plain old-fashioned terracotta flowerpots. Some plants like squash, watermelons, cucumbers, eggplant and cantaloupe will do best when started in its own pot. And some annual flower and vegetable plants like marigolds, petunias, lettuce, cabbage, onions and tomatoes don’t resent being started as a group in a single pot and are easily divided and transplanted.
In general, smaller seeds can be planted as a group – and large seeds do best when planted alone.
I like terracotta pots for starting annual flowers and some vegetable bedding plants because terracotta retains moisture, drains well and can “breath”. Clay pots work very well in hot beds or in a cold frame.
Terracotta pots are reusable year after year and are easily scrubbed out and cleaned. Because I often use an old pot, I always make sure that the pots are well scrubbed in hot soapy water before I sow seeds.
It’s important to kill any bacteria or fungus that may have been held over on the pot from the prior year.
Young seedlings grown indoors are susceptible to damping off and other troubles. When possible I use a commercial sterile seed starter mix. I find that it works best to wet the potting mix with very warm water before covering the seeds. But when I’m pinching pennies I don’t always want buy ready mixed starter. It’s expensive! Sometimes I’ll just mix 1/3 sand with 2/3 ordinary garden soil. Any soil can be made sterile by placing into into a 200°F hot oven until the soil’s temperature reaches about 170°F.
Many seeds only need heat and not light to germinate. Once seeds are up they can be moved to a warm sunny window during the day and removed to a warmer location at night.
Cantaloupe, eggplant, basil, peppers, watermelon and pumpkins all benefit from a source of steady bottom heat.Those types of seeds grow best between 65°F-80°F. In fact all cold sensitive plants do well in a hot bed that is heated from the bottom with horse manure. Some people use electric grow mats with good results. But I’ve always been too cheap to spring for an electric mat or pay for the extra electricity. My reasoning is that I garden to save money – not spend money!
The top of most refrigerators is a good warm place to start bottom heat loving seeds. That’s what I mostly do now days. But a make-shift hot bed is easily constructed with an old window sash and cinder blocks or straw bales. Just form a square or rectangle and then fill the interior with a load of about 18″-20″” of fresh horse manure on the bottom. Tamp the manure down firmly; then wet the manure with either water or urine and cover. Wait a about a week and topped off the manure with 4″- 5″ of good screened garden soil and cover again. Wait a couple of days for the soil temperature to start to rise and then plant. Be sure to vent the hot bed on warm days or you’ll cook the plants. Pretty simple really.
And just so you know, one way that you can tell if the weather is truly settled enough to plant cold sensitive bedding plants in the garden is by the size of oak leaves.
If the leaves on an oak tree are the size of mouse ears it’s safe to plant tomatoes, beans, some squash, cucumbers and corn.
For eggplant, pumpkins, peppers and cantaloupe it is better to wait for oak leaves to be more fully developed before setting them in the garden.