Getting Started with Seed Starting

First tomato plants of the season popping up

First tomato plants of the season popping up

It’s that time of year again!

This past Saturday, I gave a talk at Palladio Garden in Midtown Memphis about starting vegetables, herbs, and cut flowers from seed. As many of you are revving up for spring, I thought you might find some of this information useful.

You might wonder why on earth someone would start plants from seeds, when you can get perfectly fine transplants at any nursery or garden center. I like to start everything I grow from seed, because it is cheaper, I get more variety, and I can control inputs. That means I know exactly what went into my soil mix and on my plants, and I’m not left guessing as to what kinds of chemicals might be present.

Me with the very first handful of lisianthus I grew from seed. You probably can’t find seedlings for these stunners in your neighborhood garden center! It’s just another advantage of starting seeds yourself.

Me with the very first handful of lisianthus I grew from seed. You probably can’t find seedlings for these stunners in your neighborhood garden center! It’s just another advantage of starting seeds yourself.

Now, I know some home gardeners swear by the success they’ve had starting seeds in a little tray they picked up at a hardware store and leaving them on a sunny window sill. I’m here to squash those fantasies and tell you that if you’re committed to starting seeds at home, it takes a little investment. (Okay, so maybe saying that it is “cheaper,” isn’t exactly accurate. It can be cheaper in the long run!) To successfully and consistently grow healthy vegetable, herb, and flower starts, you need:

1) Trays. I like to plant into cell trays and set those cell trays in flat 1020 trays. That way, I can gently lift up the cell tray and pour water into the flat tray. The cell trays have holes in the bottoms of each cell that can soak up the water. This makes for a far less messy situation for starting seeds in your own home. Here is a link to Johnny’s Selected Seeds tray selection.

2) Germination Mix. Although some home growers say that potting mix works for their seeds, I like to use mixes that are specifically designed for seed-starting. My favorite is Pro-Mix with Mycorrhizae. This is a super fine mix, perfect for germination. Mycorrhizae are neat, beneficial fungi that grow on plant roots. It help extend the roots and aids in their nutrient uptake.

3) Grow Lights. This is where it can get pricey. I’ve seen people make their home seed-starting operation work with trays and clear plastic domes. It’s a lot of work, though. You have to keep the tray in a window and watch for signs of light deficiency. (That’s when your plants get “leggy.”) Then, you have to move them outside when the weather is nice. Then move it back in when it’s cold or rainy. It can be a headache! A grow light is the way to go for peace of mind and consistent seedling production. Here is a good option from Johnny’s.

Bok choy seedling grown in a Jiffy pellet

Bok choy seedling grown in a Jiffy pellet

4) Water pitchers and/or a sprayer.

5) A box fan and/or overhead fan nearby for air circulation. This will help keep fungal infections at bay!

6) Seeds, of course.

For indoor production, I also really like using Jiffy pellets. I space them out in a flat 1020 tray, and add enough water to keep them feeling damp, but not soaking wet. They’re nice, because the air is a natural barrier for root growth, and it can help keep your plants from becoming root bound. They’re especially nice for gardening with children, because they’re so easy to transplant.

It’s important to check the back of your seed packet for your specific crop’s seed starting specifications. Some flowers have to have light in order to germinate, so you shouldn’t bury them. Some crops like to be in warm soil, so you might want to invest in a heated germination mat. Most vegetables just need good seed to soil contact to germinate, but they’ll need good light as soon as they have sprouted.

Centaurea seeds are SO COOL.

Centaurea seeds are SO COOL.

Also, make sure that you’re not over-watering, as that can lead to “damping off,” which is a term for a fungal infection that can cause your seedling stems to shrivel and collapse. Good air flow helps prevent this, so make sure to have a fan nearby. Additionally, I dip my seed trays in a 10% bleach solution before reusing them to kill off any lingering pathogens.

If you are in or around zone 7b (where I am) and growing cool-weather crops like leafy greens, you can start those seeds now and transplant when it looks like your long-range forecast isn’t dipping below 30, provided that your plants have a few good sets of “true leaves.” For all of those wonderful summer crops, you’ll have to wait just a little while longer. Your seed packet will specify how long before the last frost to plant indoors, but for most summer crops, I wait until March 1st to plant indoors, and I transplant my seedlings outside between April 1st and 15th, depending on the weather. Crops like cucumbers, melons, and squash only need two or three weeks in a seed tray, so wait even longer for those.

If you are in Memphis and want to come to my next speaking gig, I am giving a talk at Palladio on April 13th at 10:00 am titled, “Incorporating Horticulture and Plant Science into the Education and Development of Children.” Also, my dear husband is giving a talk on April 6th at 10:00 am called, “Tree Law and Other Disputes Between Neighbors.” His wealth of information about the intricacies of tree law is always a hit!

You can drop any seed-starting questions in the comments below, or you can always send me an email at mary@thesouthernhorticulturist.com.

Happy growing,

Mary Riddle

Me with a gazillion seedlings.

Me with a gazillion seedlings.

Ready, Set, Tomato! (Part 1)

It's the time of year when I start really craving tomatoes. It's been months since I had a flavorful, juicy tomato, and the mealy pink things in the grocery stores right now just won't cut it. The good news is that we can start prepping now for a season of plenty.

Like all good growing, the most important thing to focus on is soil. You won't have good crops unless you have good soil. Wherever you're growing, it's a good idea to add fresh compost to your tomato beds each year. My favorite kind of compost to use is cotton burr compost. We have it in abundance here in Memphis, and I get the best results from it.

I also highly recommend double-digging your beds. (You can find my instructions for double-digging here.) Tomatoes need ample space for root growth, at least 12-18 inches. Don't think you have that kind of top soil? Double-digging helps create it! The photo below shows one of my raised beds. The foreground has been left alone, but the background has been double-dug. You can see from where my hand is that I've added four or five inches of soil space just by double-digging. Mixing in your compost amendments and loosening the lower layers of soil help the plant's root zone access essential nutrients that don't move around through the soil, like phosphorus. Aerating your soil helps water flow through your soil instead of puddling on top, which helps prevents the spread of disease.

Double-digging builds soil, as seen here. 

Double-digging builds soil, as seen here. 

After you've got your soil plan in place, it's important to figure out what kinds of tomatoes you want to grow. If you aren't interested in starting tomatoes from seeds, please consider shopping for your tomato starts at your local farmers market. Plants that you purchase at big box stores are often chemical-laden and stressed. I've seen plants at those stores with hiding aphids and early signs of disease. Buy your tomato starts from the farmer whose tomatoes you like the best. That way, your starts will probably also come with some good, region-appropriate advice. 

Here's what you should know about before selecting your tomato plants:

  • Do you want an heirloom or hybrid? Heirloom tomatoes are often beautiful, but they are much more susceptible to disease. Hybrids are often grown to be resistant to certain diseases. If your tomato patch has suffered from disease pressure in the past, I recommend going the hybrid route. 
  • You should also decide if you want indeterminate or determinate tomatoes. Determinate tomatoes flower all at once and are more compact than indeterminates. They usually bear fruit over two or three weeks, then begin to die. Indeterminate tomatoes will keep growing vines and flowering and thus require more staking, pruning, and support. 
  • Most importantly, what kind of tomatoes do you want to eat? There are cherry, beefsteak, sauce, plum, and grape tomatoes, and each one of them has their own culinary personality.

I start all of my tomatoes from seed. Personally, my three favorite varieties to grow are from Johnny's Selected Seeds, and they are Celebrity, Tiren, and Red Pearl. They're all hybrids. I like to grow hybrids, because we have heavy pressure from fungal infections in our muggy climate. I plant my seeds in 50 cell 1020 trays filled with Pro-Mix and put them under grow lights. I plant my seeds four to five weeks before I plan on planting them outdoors. I water them lightly every single day. They can germinate beautifully in trays without the use of fertilizer, but they need feeding about three weeks after germination. At that point, I soak each cell with a diluted fish emulsion mixture.

You should only start your tomatoes from seed if you can commit to lightly watering them every day. Consistent moisture is crucial while they are in trays.

 

This should be enough to get you started! I'll follow up tomorrow with information about how to transplant, fertilize, stake, and harvest. 

Tell me about your favorite tomato varieties! You can leave a comment here, or tell me all about them on one of my social media pages

Happy growing, 

Mary Riddle