It’s just about time to sow tomatoes, any earlier, and you are compromising your crop
From Old Fashioned rarely seed garden annuals to the most common of vegetables, you’d be surprised what each seed requires for temperatures, moisture and light. A little research ( even for us pro’s) pays off in the long run. I am going to review what I discovered this weekend when I decided to actually look up the specifics on what certain vegetables and flowers really prefer, even I was surprised, and, I also discovered that many seed catalogs get it wrong more often than they get it right.
First, tomatoes. Easy peasy for most of us, although the most common mistake is starting tomatoes too early. If you are having difficulties, tomatoes germinate best with some bottom heat ( I use a heating mat designed specifically for seed starting, but you can try the top of your refrigerator!. Tomatoes like warmth, with temperatures near 70 degrees. Once they emerge, I remove them from the bottom heat, and keep them near 60 degrees F. with the brightest sunlight possible, which means, they go out into the greenhouse. These seedlings in the above image are from today, March 20, which is early for me in Zone 5, but they are rootstock plants which needed an early start.
My actual crop, I sowed today. Still, a little early to sow tomatoes for zone 5. So your friend who is bragging about their tomatoes already being yay tall? You will have the last laugh when August rolls around. The younger the plant is when you plant it in the garden, the healthier and stronger it will grow. Believe me, it will catch up, and with no stress from roots being clipped, or from cool June air or soil temperatures. Even seeds sown in the garden in mid June will out shine any transplanted tomato so slow down on the ‘starting early’ ritual.
I prefer to sow tomatoes around April 15th since smaller plants grow best when transplanted, but since I am grafting some plants, I will need plants a little larger. The single greatest mistake amateur gardeners make is starting tomatoes and other plants from seed too early. Read your seed packets and catalogs ( like Johnny’s) for proper sowing dates for your area. I need 8 weeks before my final frost date, which would mean that here in central Massachusetts, Zone 5b, I would start my tomato seed on April 1st.
My heirloom tomato seeds, planted and resting on their heating pad. I am starting my plants 2 weeks earlier this year, because I will be attempting to graft some plants onto a more aggressive rootstock.
Just because your local garden center will have large tomato plants for sale in a few weeks does not mean that you should start your plants just as early. Even Mid May is too early to plant outdoors, so don’t rush. Retailers know that people will buy the first plants they can see, and their most profitable sales crop are tomatoes and summer vegetable plants that people rush to buy and plant out in April or early May, ( when soil temperatures are far too cold), resulting in either a slow crop, a repurchase after a frost, or in stunted plants that never mature properly. Start your tomatoes late, plant out smaller plants, with little stress and fewer bound roots, and never plant unless your soil or nighttime temperatures remain above 50 degrees ( which is around the first week of June, here).
Cabbage seedlings ( for early cabbage like these Fortex seedlings) must be sown in mid March for April planting and June harvest. This is an early cone-shaped form which matures fast, and is as sweet as honey and as crispy as a radish.
One would imagine that cabbage seed would prefer cool temperatures in which to germinate, but the opposite is true. Cabbage seeds love warmth, they germinate best with sustained bottom heat, and air temps 75 – 80 Degrees F. Once they germinate, they cells must be relocated to an environment where temperatures remain below 50 degrees F.
Lettuce won’t germinate unless temperatures are near or below 40 degrees F. Any warmer, and you will have leggy lettuce or reduced germination rates.
On the other hand, lettuce seeds must never experience temperatures above 50 degrees, and they germinate best when temperatures are near 40 degrees F. I move flats like this out-of-doors on sunny days in March, and keep them in the greenhouse when it gets too cold. They can be sown out in the garden as soon as the soil can be worked, since they can survive freezing temperatures if sown outside, My cell grown plants will need to be hardened off once true leaves appear, but sowing in cells will allow me to transplant them with minimal root disturbance into the garden.
These are great tips, thanks! I did that mistake last year and started my tomato seedlings too early, and therefore, they didn't really take off. Good to know!