It’s time for the annual seed/transplant primer. Hard to believe it is almost time to start veggie transplants since we just got snow dumped on us again.
What materials do you need? Seeds, soil-less bag mix, shallow containers for seed starting, larger containers for later, an adjustable height light/light rack, a small fan and of course water and time to care for your plants. Ideally, plants should be kept 4” below the lights. When they have to stretch for light is when they get thin and lanky. So, either you need chains on the lights to adjust, or use bumpers under the plant containers — situated close to a window is also helpful.
The best transplants are short, stocky and young. Tomatoes are best when they are 6-7 weeks old before going to the garden, 8 weeks for peppers, so start peppers now. Peppers, and especially tomato plants, benefit from being transplanted into graduated size pots 2-3 times before going to the garden. Using a soil-less media or seed starter mix, start seeds in a flat or similar-sized small container, about 1-2 square inches of media per seed.
When plants are 2 inches tall, transplant to a six-pack sized container, about 4-6 square inches of media per plant. The final pot size should be a 3- or 4-inch square pot or a large or extra deep six pack. The plant is repotted about every 2-2 1/2 weeks. If you only want to transplant twice, then go from the seed flat to a large or deep 6 pack size container.
A common mistake is to put a tiny plant into a large pot i.e.: a tomato transplant into a one-gallon size. The tiny plant cannot use all of the soil moisture due to the large volume and will usually rot the plant. Stay small!
Every time you change container sizes, sink the plant far enough down that the true leaves are just above the soil media level. You can bury or remove the seedling leaves — they would be the two leaves lowest on the stem.
Here’s why smaller, younger plants are better: Stem strength is critical to plants when they are transitioning from their cozy indoor spot to the brutal outdoors. Using a fan in your growing area helps to imitate wind and also keeps the plants foliage dry (disease control), however it does not imitate wind swept driving rains that plants need to be ready for. Wind damage is one of the main killers of young plants. Think of the wind this past weekend!
The smaller the plant — the closer to the ground — means less exposure (and often more flexible). You can of course use various types of plant protectors. Standing outside with an umbrella over them is not one of them. I often use a #10 can which offers great wind protection and stays on all season as shown in the photo.
Plants grown with a fan and under lights are still much weaker in cell structure than plants grown directly outside or in a greenhouse. Transplants should be hardened off, toned or transitioned (whatever you want to call it) for 5-7 days before being installed into the garden. Cut back on water during the toning period (not till the point of death!).
Many vegetable transplants can be subject to checking. This is a disorder that can occur when young plants are not transplanted up to the next pot size at the correct time and become root bound. When the plant becomes checked, it basically stops growing or the growth is stunted. This doesn’t mean it dies; it just doesn’t grow! For example, your 6-inch broccoli plant in May, is still 6 inches tall in August. Been there, seen that.
Vine crop transplants are easily damaged by winds. They are always best direct-seeded in the garden. Sometimes I start vine crops in peat pots, completely outside for best stem development, and bring them in the shop at night. This procedure closely imitates being planted directly in the garden — full outdoor exposure. I would not start them until May 1 or so. Smaller … is better!
Vine crops do not like the transplant process of being moved out of a container, so best to use peat pots and plant the pot and all. Previously, inspecting some of the inferior plants in the fall, it was noted that some barely grew out of the peat pots, having their roots restricted. So, note to self, also peel back or remove at least one side or the bottom.
I am always amazed at the folks who are excited to buy a tomato or pepper plant “with blossoms already on it!” Let me interpret that: The poor plant has been root bound for so long, and fears its life will soon be over. Fearing the end, it does what every plant does, its only purpose in life: to reproduce. So, it starts the process and pumps out flowers.
Until vegetable transplants are firmly established in your garden, you should remove any signs of bud/flower initiation. The exception would be large patio tomato plants in large pots. Only two months and we will be planting veggies outdoors!