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.)
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.
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.
The 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.
Easy, Low-Cost & Safe Gardening
I’m writing this post with the hope that we will get to plant in Perkins Park Community Garden this summer. It’s still a big IF, and even if we can open, we will likely face significant restrictions and limitations. So I’m taking a few guesses and posting some ideas to help with planning our plots. Or maybe at home you have a patch of sun and space for a 5-gallon container or window box.
Keep it simple. Now is not the time to design complicated garden layouts, especially if this gardening season is your first try. Pick one to a few things you like to grow or eat. It’s okay to leave open space, but plan to mulch those areas if you can (see below). And know that even if we open up, there’s always a chance we could get shut down again if the pandemic worsens.
Try No- or Low-Dig Gardening. If ever there was a good year to try a more tools-off approach to garden prep, this may be the one, when our tool shed may not be open. See here and here for the rationale and potential benefits of no-dig gardening.
Mulch. Last fall, many of us mulched our gardens with leaves and other material, which can be brushed into the areas among new plantings (keep young plant stems clear of mulch). But if your plot is bare, laying down some mulch will save some work later by (1) blocking weeds, (2) improving water retention, (3) building more fertile soil and (4) protecting plants from soil-born diseases. If you use leaves from PPCG and have a tool like a hoe or rake, chop them up a bit so that they don’t form a dense mat that blocks water. Or use corrugated cardboard or brown paper lawn refuse bags/grocery bags, or multiple layers of newspaper. Weight it all down with rocks, jugs of water, etc.. Added bonus: worms love this stuff.
Be Water Wise. We may need to haul our water to the garden, or we may not be able to share hoses and watering cans, so just in case, start saving up those gallon jugs, beverage containers, etc. with caps. (This is one other good reason to keep your garden plan very simple.) Also, once your plants are established, work on watering deeply and less frequently to encourage the development of deep roots and more drought-tolerant plants. See here for more ideas and lists of drought-tolerant plants. And here’s another post on preparing for drought.
Improvise and use what you have and limit your trips out to the stores.
- Kitchen implements such as serving spoons and forks can work as garden hand tools. Paper grocery bags and newspaper work great as mulch. Milk jugs can act as mini greenhouses or pest protection (just be sure to vent them). Use scraps of old textiles for tying plants. Scavenge fallen branches to support tomatoes and create garden trellises.
- More garden hacks here and here.
- Ordering of seeds is delayed at many sites. How about that old packet of seeds? Are they still good? Use them if you can. Test a few seeds out to see if they sprout using this method. See here, this Black-Eyed Susan vine (front, middle) planted on April 1, now nearly 1.5 months later? It sprouted, but lost its oomph. Poor girl. But many other seeds will do just fine from year to year. More seed-starting tips here.
- The Lowe’s parking lot in Weymouth has been almost as crowded as Pond Meadow Park. (Not really, but PMP is unruly these days.) If you must go out and buy anything, try some outdoor garden centers that may be less crowded, such as Christopher’s Garden Shop and Farm Stand (Facebook link) in Weymouth or the Artery Garden Center at 625 Southern Artery in Quincy (in Goodwill parking lot).
- Non-profit organizations that rely on annual seedling sales are being responsive to the pandemic and are coming up with safe shopping alternatives. See Marshfield, City Natives, and Holy Hill Farm. Stay tuned for Brookwood Farm, which is evaluating its inventory.
- Does your grocery store or other essential shopping stop sell seeds? A few weeks ago, Kam Man had seed displays filled with a nice selection of Asian greens and other veggies not typically found in the Burpee racks at Home Depot.
- It can be hard to start plants from seed at the garden. They need extra watering care until they germinate and as seedlings. There may be pest pressure. Or if we get a big rainstorm, your seeds/seedlings may be washed away. Instead, start seedlings at home for transplant or purchase plants that are ready to be planted out in the garden.
- Look for F1 or hybrid varieties that are more resistant to diseases than heirloom varieties.
- Look for quick-maturing varieties. New Girl tomato, for example, matures in 62 days, whereas Grand Marshall takes 78 days. That’s a big difference. (Be aware, too, that in late summer, shade on the southern edge of PPCG grows long and will lengthen your ‘days to maturity.’)
- Look for easy-to-grow crops. I like this article from High Mowing Seeds, which includes a planting schedule example. One note: zucchini isn’t impossible to grow at PPCG, but we do have some pressure from the dreaded squash vine borer.
It’s almost never too late. Even though we are coming upon the time when we could be planting our second succession of crops (warm-weather crops such as tomatoes, green beans, cucumbers, and peppers), there’s still plenty of time ahead for a third “slot” for planting (quick-growing warm-weather crops and cool weather fall crops).
Hope to see you soon!
What To Do This Spring While PPCG Is Closed
Check out The Trustees at Home, with links on gardening, virtual nature, keeping the kids busy, and more.
Complete a free vegetable gardening module from Oregon State University’s Master Gardener program. Some of the information in this program may be best suited for Oregon’s growing climate, but most looks like it’s relevant to us.
Follow the Insect Xaminer, a short video series from UMass Extension starting with (drum roll) the Gypsy Moth caterpillar. This first installment is quirky-gruesome in the context of the pandemic, but I’m sticking with the series for its promised information on common insect pests.
Try a modified version of a technique known as winter sowing. I’m not encouraging anyone to run out to the store to buy anything, but if you can get your hands on a milk jug (or similar container functioning as a mini greenhouse), a small bag of seed-starting mix, and some lettuce seeds, cilantro, or spring onions, you can grow outside in a small, sunny space.
- Because these plants like cold, you’ll have to open your containers on warm days or they’ll cook.
- Once they are established with a few sets of leaves, you can probably leave the top off for good, unless we have an overnight with temps down into the 20s F.
- I’ve never tried it, but some gardeners even start up their warm weather plants (around now) in this fashion, though again, you’ll have to keep an eye on the weather. If we get a cold snap, throw a blanket over them.
- There are a few benefits to protected outdoor sowing of garden plants. They’ll receive more light outdoors. (Even a sunny windowsill might not be bright enough for your plants, even if it looks bright to you.) Plus you won’t need to harden them off if you transfer them to a larger growing space. Just be aware that I don’t know when we’ll be able to get back in the gardens.
Holly Hill Farm–which like many other businesses is in need of our support–appears to still be having its early plant sale on April 18 & 19. (Their warm-weather plant sale usually happens in May.) Keep an eye on their website and/or sign up for email updates. They have altered their sales methods in response to COVID-19 concerns.
Stay tuned for more details from Braintree Farmers Market. They went to a virtual model on April 4, and it looks like the next date is May 2.
Download/stream the Birdsong radio app from RSPB.
Check out great gardening titles on Hoopla, available for free through Thayer Public Library.
Read all about why we need green spaces in The Wild Remedy, part illustrated diary, part scientific review of the mental health benefits derived from nature.
Go for a walk in any of the other numerous parks that are still open, such as DCR parks. Or try Great Esker Park in Weymouth, which was nearly empty on a sunny day this week. For further info, here are links to the state’s assemblage guidelines and stay-at-home advisory.
Other ideas/comments? Please share below.
Photo credit: Gary R.
Five Indoor Seed-Starting Tips from Margaret Roach’s A Way to Garden
Select Seeds Suited for Indoor Sowing and Transplanting
Many crops start well indoors–and need the extra growing time in a protected space while the weather is still too cold–but a few grow better when sown directly in the garden. There aren’t any no-break rules here. Even carrots can be transplanted, though it’s not generally recommended. Especially if you are trying a crop for the first time, read the seed packet for instructions on which method typically works best. Pay attention, too, to the days to maturity information and your crop’s cold tolerance to help decide where and when to sow.
Start with Good Materials
- Clean your seed-starting containers with a 1:9 bleach:water solution or soapy water.
- Use a sterile grow medium formulated for seed-starting.
- For best results, use fresh seeds. (See this link to a chart on seed viability and a great discussion on the difference between viability and vigor. More info here.)
Keep your planting medium evenly moist until your seeds sprout, then let it dry out slightly between watering. In no instance should it be soggy or bone dry. Be gentle if you water on top and use a mister or similar method. Bottom watering avoids the problem of dislodging seeds and young transplants and helps prevent diseases.
Get the Light Right
This one is Margaret Roach’s most emphasized tip. Seedlings will need supplemental lighting–more than they’ll likely get on your windowsill–or they’ll grow tall and spindly.
For Perkins Park Gardeners: What to do if you don’t have a fancy grow light set up and still want to sow your own seeds for transplanting?
- Try inexpensive shop lights. I’ve had reasonable success growing seedlings with a couple of shop lights purchased for around $15 at Ocean State.
- Squeeze one or two cell packs on your windowsill and supplement with a simple clamp light fixture (bulb separate). Set them outside on warm-enough days, taking care to harden them off (see next tip) along the way.
Take Time to Transplant with Care
Harden off plants before you transplant them to their final space in the garden. They’ll need to gradually acclimate to outdoor conditions, especially to the sun. Start with no more than 1 hour outside in direct sun on the first day (not midday) and gradually increase the time of outdoor exposure over the course of about a week. You’ll know you’ve overdone it if you see bleached or brown and crispy patches on your plants’ leaves. Alternatively, some people like to choose overcast days, leaving them outside during daytime hours for a few days.
Once you’ve gotten your plants hardened off, make sure you’re not rushing to get your plant in the garden too early, before you are reasonably clear of of unsuitable weather.
For more seed-starting tips (and more):
A Way to Garden by Margaret Roach (2019).
For a wide range of seed-starting information, see Margaret Roach’s website.