Tag: Seed-Starting

What in the Devil Is This? Purple Leaf Edition

Categories Diagnosis, Gardening Techniques, Plant SpotlightLeave a Comment on What in the Devil Is This? Purple Leaf Edition

This spring, a whole flat of marigolds turned purple. So purple, they were almost black.

The marigolds, Durango Outback variety, have been garden stalwarts, the kind I don’t have to fuss with to get good performance. I like their pom-pom blooms, which show up well in dark areas of the garden with only a few hours of daily sun. Normally their leaves are green.

A quick Google search turned up a lot of discussion about purple leaves in tomatoes (see links below), but also plenty about marigolds. I’ve seen discolored leaves on marigolds before, but they look more like the photo here, with reddish-purple around the edges of the leaves. The color is anthocynin, a water-soluble pigment ranging from red-purple to purple-black that develops under a number of different conditions. Sometimes seedlings will tinge with anthocynin for a brief period of time in their stems, for example, as part of their natural development. Or, here, this basil variety will develop purple-red leaves that are normally high in anthocynin. (Younger seedling on left; in this case, I would get concerned if the color didn’t show up purple.)IMG_20200520_090443919

Anthocynin production is also a stress reaction that may help the plant survive a number of adverse environmental conditions, including cold, drought, light stress, and deficiencies in nitrogen, phosphorus, or both.

With regard to my marigolds, I ruled out cold and drought and started with nutrient considerations. Because I’d been growing in a soilless seed-starting mixture (Roots Organics Microgreens) that contains no added fertilizer, I’d supplemented with a liquid 2-3-2 Gardens Alive fertilizer at half-dose once per week. Giving a second half-dose feeding helped a little within a few days, but not much.

Before I gave them another feeding, I considered a third factor: my new lighting, a set of inexpensive shop lights I’d purchased to grow microgreens over the winter. The shop lights had performed well for trays of pea shoots and broccoli, sunflower, and lettuce microgreens. Given that success, I’d figured they’d do at least all right for seedlings, and in fact, most of my other seedlings were fine. (I’d even managed to get some micro tomatoes to flower under them.) Still, I moved half of the marigold seedlings to a full-spectrum grow light and left the other half under the shop lights. Within a few days, here’s what happened.DSC_3327

Shown above, the plants on the left have a few more days under the plant grow lights. I saw enough change within that time to convince me I’d hit on the solution.

Let’s talk a little more about those shop lights, because there’s a lot to know about lighting. For starters, visual perception of light and the specs on most lighting packaging don’t provide enough information for growers. What looks bright to the human eye might not be the right light for a plant at the intensity it needs. Although a whole winter of microgreens grew well under those inexpensive shop lights, crops that are grown simply for seedlings have different requirements from crops that are grown for mature plants. On top of that factor, each crop has a different set of light requirements for optimum mature growth.

IMG_20200602_161709548_BURST000_COVERThe takeaway: inexpensive shop lighting works all right for certain crops, but not for others. I’m sure there’s great variation among shop lighting, as well, and it’s difficult to determine exactly how much/what kind of light plants are receiving without a special light meter. I will continue to use the shop lights for certain crops and give my premium grow light space to those plants that need it.

Sources/ For Further Reading

Gardening Under Lights by Leslie Halleck. Available for free from Hoopla. This is such a great resource, I ordered a hard copy of it.

This gardener’s purple marigold leaves may have resulted from cold temperatures.

Causes of phosphorus deficiency. The fix is more complicated than adding more phosphorus.

Environmental Significance of Anthocyanins in Plant Stress Response.

Abiotic Stresses Induce Different Localizations of Anthocyanins in Arabidopsis.

Causes of tomato leaves purpling.

Brief YouTube video, phosphorus deficiency in tomato plants.

Purple leaf disorder in tomatoes.

Indoor Seed-Starting Tips

Categories For Beginners, Spring Gardening, Start HereLeave a Comment on Indoor Seed-Starting Tips

There’s a lot of information out there about starting seeds indoors. While there are definitely better ways to grow seeds, a certain amount of fudging is acceptable. Here in our house, we’ve had our share of seedlings that came home in Dixie cups from elementary school and fared just fine.

Still, if you want to boost your success and the health of your plants, take a look at these tips. By growing from seed, you’ll have a greater selection of varieties from which to choose.

1) Use clean, well-draining containers, such as recycled cell packs from last season. Soak IMG_20180224_110315670.jpgthem in a 10% bleach solution for 10 minutes.

2) Don’t use garden soil: it’s not sterile, it’s too dense for tender seedlings, and won’t drain well.

This seed-starting mix with peat as its main ingredient is relatively cheap (around $5), OMRI-listed, and easy to find at Home Depot.

Personally I don’t like the little peat discs that puff up when soaked in water because it’s too difficult to control their moisture  content and they usually end up quite wet.

You want to moisten your soil until it’s damp and holds together, not drench it until it’s dripping.

3) About those seeds…

  • At PPCG, you do not have to select organic seeds to grow organically. Choose them if you don’t mind spending a little extra money to support organic production of seeds. Usually you will find a wider selection of non-organic varieties.
  • Follow the directions on the seed package with regard to how deep to plant the seeds.  Some seeds need light to germinate and should simply be gently pressed onto the top of the soil; others need to be planted deeper.
  • Plant 2-3 seeds per cell (or whatever kind of container you’re using). After they sprout, choose the best seedling in each cell and clip the rest. (Don’t pull out the extras to avoid disrupting roots.)
  • If you’re carrying seeds over from last year’s stash, expect a lower germination rate. Here’s a way to test your seed viability.
  • For some crops, direct-sowing in the garden is better, either because they don’t transplant well or they grow quickly (and often early) enough that you don’t need to start them indoors. These include: beans, beets, carrots, cucumbers, peas, radishes, salad greens, squash, sweet corn, and turnips.

4) Seeds like a little bit of warmth to germinate. Seed-starting warming mats help along the germination process. Or try a warm spot in your house, such as the top of your refrigerator, but remember to keep a check on them.

5) Keep them moist, too. If you stick them in a bag like this, they should be all set for a IMG_20180224_114143841.jpgfew days.

6) But once they’ve sprouted, they like cooler temps in the 60s. Get them under the lights and take them out of plastic right away.

If your seedlings start to get tall and spindly, they might be too warm or not have enough light.

Sixteen hours is best, which is why I did invest in a grow light.

Prop them up so they’re right under the light, about 3 or 4 inches away. Keep adjusting them so that as they grow, the leaves do not touch the light.

Here’s another trick to try: cover sheets of cardboard with aluminum foil and position them to reflect light from a window, etc. back onto your plants.

7) And finally, if all of this sounds like too much of a bother, skip it all and watch for the great plant sales we have in our area.