Constructing a Cold Frame

This weekend, I built a cold frame.  The project has been on my wish list for a while.  I’ve had issues with getting seeds started with our couple-times-a-year gully washers.  This simple structure will provide me with protection from rain to start perennial and cool-season annuals with the added bonus of a couple degrees of extra warmth at night.

I had in mind what I was trying to construct since I built them as a teenager back in Tennessee based on Eliot Coleman’s designs.  A walk around the hardware store, and I was able to piece together my project.  I decided on a smaller size (3 × 6 ft) than my usual 4 × 8 ft because that 18 sq ft was the largest pane of plexiglass I could find.  I also chose pine as my wood. There’s a cedar lumberyard about an hour away, and for future frames I’ll use that wood. But, I was in a hurry to get it built before the semester started, and it will work well for a few years.

First step before building the box was to build the wooden frame to the piece of plexiglass to create a light, the name of the pane of glass on a cold frame. You want to make sure that the light fits the box snug.

Here’s the light constructed with the plexiglass attached to the wooden frame. I used braces on the joints to make sure it stays sturdy. I used a PVC-rated drill bit and drilled slowly into the plexiglass. The guy at the hardware store told me to leave the protective coating of plastic on the glass to help drill through it. If the protective layers are absent, he said a piece of tape would help to protect the glass from shattering when drilled.

A bolt and washer hold the plexiglass on the wooden frame, and to the right is a handle for the light.

I constructed the box out of two ten-foot long 2 × 12’s cut into two pieces—6 ft long for the front and back and 3 ft long for the sides. To create a slope on the top of the box to maximize sun exposure, I cut 4 in off one of the 6 ft boards to make it 8 in tall, and for the side boards, I cut a slant (1.3 in drop per 1 ft board length). Once constructed on the ground, the cold frame is turned over so that the front and back boards have a slight slant in one direction and so that the top is flush with the light. Notches made in the middle front and back allow the installation of a support beam.

With the ground cleared, a nice mulch of leaves will help to keep weeds down and support the trays to keep them from sitting on the ground.

Finished product!

It was a quick project and only took me 3 hours to make. The total cost of supplies was around $160 to cover 18 square feet (~8.90 per square foot), which is cheaper from most of the models on the market. If I could do it over again, I would try to figure out a way to reduce the size of the cross beams across the light that block some of the solar radiation. Soon, I’ll also add strips along the bottom of the frame to help protect the wood from rotting, which is another suggestion from Eliot Coleman’s design. I also want to attach the light to the box and cut a notched piece of wood to open the frame to the desired height during the day.

But, overall I’m pleased with how it turned out, and I look forward to having better success growing plants.

Goatweed Leafwing

I was in our edible patch this afternoon when a flicker of crimson silently swooped past me. I was surprised and caught off guard to see a butterfly circling. At first glance I wondered if it was a Gulf Fritillary. However, it didn’t match my mental image of one, and it is winter.

It landed near the fence, and I went over to investigate. At one point, it sensed me. The frail creature played dead and closed its wings to reveal incredible camouflage! It looked just like the fallen leaves around it. I snapped some pictures and took some video to try to identify it before I helped it get airborne again. A quick google search revealed I had encountered a winter form of Goatweed Leafwing, a name that sounds more like random words shouted in charades than a gorgeous and fascinating butterfly. The summer form’s color is a bit more drab orange.

Amazing, eh?! Look at how the Goatweed Leafwing looks just like the oak leaves around it. Its pinnate and reticulate venation pattern game is strong.

Eventually, it landed in an eastern red cedar. And, I leaned over a barbed wire fence and held the camera high to try to get some good detail of the Goatweed Leafwing.

The name describes both its plant host and plant mimicry. Goatweed (aka Croton capitatum) is the larval food source along with Texas croton (Croton texensis) and prairie tea (Croton monanthogynus). That’s it for plant hosts, which made me ponder planting some weedy Croton in my yard. Only for a second, though; it is everywhere along the roadsides. The leafwing part alludes to the underside of the wing resembling fallen foliage.

I spent part of the rest of the afternoon thinking about how in the world does an insect that’s a host on one herbaceous plant evolve to look like a dead tree leaf? Research supports that it occurred step by step in Kallima, another butterfly that resembles a dead leaf. (Here’s the official paper or the National Geographic CliffsNotes version.) That’s likely the case with my new friend. These leafwing mimics evolve a bit to look like a leaf, which decreases the chance they’ll get eaten. And, over time, these changes accumulate. A line that looks like a vein here, a reticulate vein pattern there, and less and less adults get eaten.

Discovering this species today filled me with wonder and helped me better understand the ecological history of this area. It was a fun find for a gray day.

Mowing the Food Prairies

Today, we mowed the food prairies, our prototype herbaceous plantings at SFA.  I was hoping to wait till January 22nd to have a lab the first week of class and teach students about mowing naturalistic plantings.  However, with the warm weather the underplanted Narcissus × odorus had flower buds emerging from the soil.  This problem is one I outlined in detail in a previous post.  

I did get to show Anna Claire and Jevon, two of our Plantery student apprentices how mowing is accomplished.  For clearing the vegetation, I was inspired last year from a video Austin Eischeid posted to just raise a push mower on the highest setting and rev it into action.  

Jevon mows!

Anna Claire mows!

Some plants that lay over need to be pulled up to come in contact with the mower blades.

This year is our second mowing of the food prairies, and it went off without a hitch.  It took about 40 minutes to mow 650 square feet, but that includes some down time to refill the mower with gas.  

I prefer to mow when we can because the ground up residue provides a mulch that prevents weed growth for much of the rest of the growing season.  Even late into the fall of 2018 I was able to find ground up grass clippings from the January 2018 mowing.  

The finished product. Notice the nice layer of chopped plant residue. It is amazing to see 3 to 4 feet of biomass reduced to a few inches. The deep green clumps are Carex cherokeensis.

And, we were able to find Narcissus × odorus buds still intact after the cut. Mission accomplished.  

Oh, and here’s a video from last year if you want to see the process. Yes, our students do really mow that fast.

Natural Grafts

One of the questions I get about grafting is how in the world did people discover that you could take two different plants and combine their disparate tissues together?  

I think people of old knew grafting was possible because they had seen plant tissues recombine in nature.  Naturalists were outside surveying their environment, and from what they learned from nature, they applied that knowledge to grow plants better.  

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We have a massive chinquapin oak (Quercus muehlenbergii) in our front yard in Tennessee.  A few years ago, I noticed for the first time in our thirty years of living there that it has a natural graft on the back side.  It is more unusual than most that I’ve seen because three branches come together.  

The winter frame of chinquapin oak

Thread this needle. On the back side of the tree is this natural graft where three branches have become one.

Here’s a side shot. You can see a branch behind curve up and down to merge with the other two branches.

These natural grafts have been known to occur for a long time.  This bulletin from Kew printed in 1917 (over 100 years ago!) describes the process well.  Branches rub off the outer bark in the wind, callus (wound) tissue forms, and eventually the tissues on the two limbs grow and conjoin together.  It is so fascinating to think about the process of how the vascular tissues of large branches can realign and to witness the products of a years-long process.  

This Week in the Garden: Broccoli Ready for Harvest

I returned home from holiday travel to find my broccoli ready to harvest.  I was delighted to see about 15 speckled-blue balloons rising from the forest of glaucous leaves.  

I tried two new cultivars this year—‘Dura-Pak 16’ and ‘Burney’.  These two varieties caught my eye flipping through the Twilley seed catalog because they were listed as part of the Eastern Broccoli Project, an effort to develop broccoli cultivars for the eastern and southern US that tolerate our warmer nights, have flatter heads to shed rain, and root systems that are more tolerant of wet soils.

It was certainly a good year to evaluate their adaptability to wetness.   Greg Grant posted online the other day we’ve gotten 82 inches of rain this past year.  Just since September 1, 45 inches have fallen!  That explains why I’ve had a creek running through my yard since October.  

The plugs also got into the ground a little late, but it’s not uncommon for me to be harvesting broccoli in December and January.  Now, I’m curious to see how these types do on the other end of the cool-season spectrum.  We shall see come later this spring.  

One of my favorite ways to cook broccoli is a recipe learned from Alton Brown’s Good Eats.  Wash it well.  Quarter the florets and stems.  Put it in a skillet with about a 1/4 cup of water.  Turn the heat on high for three minutes and then low for three minutes.  Add some butter and salt, and you’re good to go.  

The buds of ‘Dura-Pak 16’ are quite tight.

‘Burney’ buds are getting a little large, but they’re still delicious for eating.

Students Showcase an Interest in Horticulture

This weekend, it was my turn to help out with Showcase Saturday, an opportunity for high school students considering SFA to come check out our school’s diversity of majors. When I’ve assisted in the past, we have at most two or three students come up to our agriculture department booth and ask questions about our horticulture program. I expected the same turnout.

But, by the time I left, we had TEN students who had came by and expressed interest in horticulture. I was amazed. From the time the event started at 1:30, I felt like I was talking to students for 45 minutes straight. One student had even come six hours from Oklahoma with her parents because she heard that our program was really good, and she was looking at it over other programs near her home! (In full disclosure, they were headed to her grandparents who lived about an hour away, but still! I was impressed!)

They came with questions about our program, what we offered and how we were different from other universities, and what career opportunities were available after graduation. Not all of them knew the word horticulture. Some came saying they were interested in growing plants or hydroponics.

After my amazement wore off from the constant stream of students interested in growing plants, my analytic scientist brain switched on, and I started asking questions such as how did you even hear about horticulture, a word that normally has low recognition amongst youngsters. The common thread was high school opportunities—classes for horticulture and/or participating in floral design or nursery competitions in FFA. These comments helped to support a trend I’ve seen of more and more high schools offering horticulture classes and doing greenhouse projects. (Even mine back in Tennessee built a greenhouse right after I left!) I would like to see some hard data, but I think there’s something there.

Time will tell if they actually decide on horticulture as a major, but the students’ comments reminded me of what I’ve been preaching. For people to engage with horticulture and plants, they have to come into contact and imbibe the wonder of plants or else this potential passion in many students may lie dormant.

Yes, we have to accept not every seed is viable. Even Aldo Leopold realized, “There are some who can live without wild things and some who cannot.” I believe the same dichotomy applies to encouraging an interest in plants and even pursuing a career in horticulture. But, visiting with the students this weekend reminded me we must be present and keep reaching out to those that love the wild green things in anyway that we can, even if their love hasn’t germinated yet. It did in me, it did in you, and it will in them.

Magnolia Seed, Spooky Stuff

“Have these things always looked like this?,” Karen asked with a hint of surprise in her voice.

Even though my back was turned as I stood at the kitchen sink, I knew exactly what had caught her eye.

A few days earlier I had plucked some ripe fruit from a Magnolia grandiflora in our yard that had colored up very nicely. They were easy to find on the ground and in the tree with their blushed, knobby appearance. I brought them indoors and was inspired to put them in a bowl on our table from seeing them top containers a few autumns ago at the Scott Arboretum. Such a clever use!

When I brought them inside, the fruiting bodies were sealed shut, but a few days in the house and the follicles on the aggregate structure started to split open and reveal their vermillion-colored seeds inside.

“They look like painted witch fingernails growing out of these things,” Karen continued. Both she and her sister who was visiting from out of town indicated they looked a bit freaky. It was nearing Halloween, and we had just watched Hocus Pocus a few nights earlier. I could see how seeds that magically appear overnight growing out of a structure could be a bit spooky and repulsive.

I, however, was delighted to see the seeds. We want more Magnolia trees on our property. Most years I’m too late getting to a tree to collect the little rubies because the birds and mammals get to the goods first. But, the propagules were right on my table for the picking.

In prepping for sowing in the past, I’ve removed the outer aril scrapping them with my own fingernails. However, one of the tricks I learned from reading Andrew Bunting’s book The Plant Lover’s Guide to Magnolias and a blog post he wrote during his tenure at the Scott Arboretum is soaking the seeds for three days in water will aid in removing the red arils that cover the surface along with any associated eeriness one might perceive.

Tonight, I plucked the last of the seeds from the follicles and plopped them into water-filled mason jars on our kitchen windowsill. After they’re cleaned, I’ll sow them in some damp growing media in a ziplock bag, stick it in the fridge for a couple of months to help overcome dormancy, and sow them in late winter.

I just hope no one confuses this batch in our fridge for chocolate cake mix.

Cone-like fruit of Magnolia top dress a container at the Scott Arboretum. You have to admit that the seeds emerging in the bottom left look a bit demonish.

The Old Factories

The door has closed for good on the old factory. Once full of the hustle and bustle of making, the air inside is now still and quiet. The essentials were moved out and relocated. All that’s left is a lifeless skeleton.

And, then the factory falls. From some lofty branch, this once photosynthetic powerhouse takes a whimsical whirl to the ground. Its landing spot is as uncertain as is its future.

Many view these factories with scorn. They burn them, demolish them, toss them to the curb. Anything to make the abandoned structures vanish and keep up the block.

But, I enjoy the old factories.

I enjoy shuffling through their midst. Their stark colors pop against the verdant turf. In some, the incandescent glow hasn’t been turned off just yet and still beam of color from livelier days. Where the wind takes them, they congregate and delineate fencerow and field alike. In such piles, kicking their stolid walls in a stiff breeze animates them once more.

I also enjoy how the old factories enhance the neighborhood. Arthropod entrepreneurs move in and bring a second life to these empty vessels. These remnants become hangout places for fungi and fun girl alike. Soon, the smell of brewed geosmin and earthy smells is on every corner. Graffiti and murals from earthworms and beetles appear overnight. Gentrification, right out my back door.

Yes, I enjoy the old factories. And, I wouldn’t get rid of them for the world.

With the arrival of November, I find myself raking leaves. And, being surrounded by trees on two and a half acres, we have plenty to use. Some have started to drop in earnest while others still hold fast. The succession helps this collector of fallen foliage.

While many gardeners herd them to the curb, to me each leaf is precious and nary a one leaves our property. For years, I’ve considered the litter quite valuable. Even as a teenager, I’d pile them up to make leaf mold and use this black gold to mulch plants the following year.

I keep my greed in check. Many that fall lie where they land for most of the winter. But, in areas where they are plentiful, I relocate them by the wheelbarrow load from the lawn to garden beds. A thin layer keeps the weeds down around vegetables, perennials, and woodies, and a thick layer smoothers the grass (save for the dastardly Bermuda!) to help create new planting areas. That’s exactly what I’m doing around our fig saplings. In the spring, this blanket will be plugged with grasses to create a groundcover matrix.

Some beds that I mulched last fall still have an icing of last year’s leaves. Amazing, no? They need a new coating as a few weeds are gaining hold, but still I’m impressed that they’ve persisted for so long.

Yes, I wouldn’t get rid of them for the world.

I'm Digging Peanuts

I dug peanuts the other night for the first time ever. I did the math and determined that approximately 130 days had passed since I shelled the seeds and thumbed them into the ground. Still wanting to garden after the sundown in a month of shortening days, I decided their time had come. I turned on our side door lights, grabbed the pitchfork, and stepped off into our kitchen garden to start prying them up.

We don't have very many plants in the ground—maybe 30–40 in a bed ten feet long. I was wanting to trial them out here in east Texas before I went gung-ho planting. With this small space, I didn’t expect the harvest to take too long or be too difficult.

The only hindrance was finding where a plant’s crown was. It wasn’t the dark that hid them but the long shoots. 'African Runner' was really living up to its name as shoots two feet or longer weaved together to form an amorphous mass of foliage.

A few pries from the fork along the edge, and they slipped right out of the ground with a gentle tug. I was surprised to see the peanuts holding onto the plant so well from the little pedicles. Having just dug sweet potatoes a few weeks back, I figured they’d be breaking off left and right to escape the harvest and remain in their underground sanctuary.

After digging, I laid them upside down to let the plants wilt a bit and called it a night. A rain the next day washed most of the soil off and made removing the chthonic fruit from the plant a much cleaner job. Karen even helped a bit, and by the end of sorting through the legumes, we had over a gallon bucket’s worth. Plenty for next year, Pad Thai, roasting and salting, and maybe even some peanut brittle if I’m adventurous.

Peanuts galore.

Overall, I was quite pleased with their performance. They made a spectacular groundcover during our fierce summer; therefore, I’m considering integrating them with summer crops like sunflowers and corn. Get the taller plant growing and then come behind with peanuts. Their nitrogen fixing ability is a plus as I explore using more functional cover crops here.

A Sweet Harvest

My first job was working two summers during high school at a sweet potato farm just over the county line in McConnell, Tennessee.  Mom got me the gig.  Fred’s Plant Farm was owned by one of her co-workers, and he was looking for weekend and summer help.  Every Saturday morning till I got my license Mom drove me to work.  It was hot work, but as I reflect on those sultry days, I have fond pastoral memories of working on a farm. 

The plant farm's claim to fame was once having their sweet potatoes mentioned on the Martha Stewart show.  It wasn’t the large storage roots we dug each fall that Martha had mentioned.  No, what she had purchased were sweet potato slips, short adventitious shoots that arise from the storage root.  These were the mainstay of the company and easily shipped across the country to tv mogul and master gardener alike.  Selling large sweet potato roots in rickety wooden bushel baskets was just a bonus.

Before I arrived, I knew very little about this root vegetable that thrives in our southeast weather.  At the time, I didn’t even like sweet potatoes.  But working on the farm gave me a great crash course of how to cultivate this southern staple.  To produce the slips, we erected wooden beds about 10 feet wide and 100 feet long initially in a hoop house and then built them outdoors once it warmed enough to pass the fear of freezes.  We leveled the soil, poured the sweet potatoes in by the bushel, and then topped them off with four inches of fresh sawdust.  As the sawdust heated, it nudged them along into sprouting. 

Sweet potato slips grown in a bed of sawdust. The propagules are pulled, bundled, and shipped around the country.

We waited I don’t know how many weeks for the shoots to emerge in the cool spring.  I was so eager to see the little tops push out of the substrate I dreamed one night that I walked into the hoophouse and discovered hundreds of them sprouting.  The next day at work, lo and behold I found some emerging.  After they appeared was when the real work began. We would spend hours pulling sweet potatoes in bundles of 50.  These would be packaged and shipped off.  The last of the batch would become our starts for the fields.  Once planted, they grew until harvested in autumn and then were stored over winter until the whole process would repeat again the following spring. 

Sweet potatoes growing in a field just outside Martin, Tennessee. These will be harvested and used for next year’s starts.

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Ten years later, I’m growing sweet potatoes again.  But, now I LOVE LOVE LOVE these sweet and nutritious delicacies:  sliced and diced with cajun seasoning, mashed with butter and salt, or in sweet potato casserole (or as my friend Stewart Thomas calls the dish butter and brown sugar casserole with a bit of sweet potatoes).  The casserole was what converted me.  A recipe my mom found won 1st place at a cooking contest in Tennessee, and it didn’t rely on any of that extra marshmallow or raisin fluff. 

As much as I love them, it can be hard to find slips every year to purchase, and sometimes they can be quite expensive.  Sweet potatoes are an asexually propagated crop.  Most organs that we store as vegetative propagules like sweet potatoes, Irish potatoes (which is a swollen stem, not a root), garlic (which are swollen leaves, not a root), and the like we don’t store as seed.  These fleshy organs are still metabolically active whereas many seed are dormant or in a resting state just waiting on water.  Therefore, they won’t keep as long as say those tomato seeds from five years ago in the back of your fridge.  That’s why they must be constantly regenerated.  Hence the need to go slip to root to slip. 

To get slips I took a lesson from my farm experiences as a teenager, and I grow my own.  First, I propagated a few at SFA and watched students enjoy learning how to start the little slivers.  I got my starts for school a few summers ago from George’s Plant Farm in Martin, TN.  Funny that the one place I could find several different varieties available in the whole country was only about 30 minutes from my Tennessee home.  We planted them out, and the following fall my Fruit and Vegetable Production class harvested over 90 lbs of sweet potatoes.  We averaged 1.6 lbs for ‘Beauregard’ and 0.6 lbs for ‘Purple Passion’.

A sweet potato slip grown by a student at SFA. Probably named so because they slip right out of the substrate with a nice jerk from above.

After harvest, I had the students grade the sweet potatoes into large and small roots just like we did back at the farm.    The large ones we sold in our garden market, and the small ones we stored in our classroom for forcing later in the spring.  When time came the next year, we used four-inch-deep nursery trays to start our slips.  We covered them with potting substrate, placed the trays in the greenhouse, and less than a month later the shoots were ready to pull.  If left too long, you could quickly see where the genus gets the name Ipomoea, which means worm-like.  The shoots will grow and wriggle all over the table even from the little bit of soil in the tray.  

Once slips are pulled, a quick jab and pry forward and back with a sturdy shovel makes a good planting hole.  We stick the shoots in, and they form roots very quickly.  Well, let’s be technical.  The latent roots already in the stem emerge quickly.  That’s right, sweet potato stems have roots up and down their length as does tomatoes, coleus, and willow that enable them to quickly gain purchase to new soil or if damage occurs to the stem.  Cuttings I’ve taken in the past put out roots within two days in water.

This year at my house, I’ve played around with making starts, too.  I took some leftover ‘Beauregard’ and ‘O’Henry’ sweet potatoes we purchased, nestled them just under the soil, covered them with a few inches of leaf mold, and less than two weeks later I saw wee little shoots poking out.  After they got a few leaves on them, I pulled them out of the ground, and stuck them into a bed.  They’ve grown beautifully over the summer excluded from deer by our double fence that surrounds our patch. 

Sweet potatoes are excellent soil covers as you can see in the image above. If you can keep them clean early on, they will seal their canopy and prevent weeds from germinating. However, I left the Rhus seedling in the back right corner to be moved to our prairie.

This past week marked approximately 100 days since planting, and the fresh rains that have fallen loosened the soil.  Time to dig sweet potatoes!  I cut the foliage off and carried it to the compost pile.  Then, with the pitchfork I jabbed straight down into the ground careful not to puncture the storage roots, pried the swollen treasure out, and moved down the bed to unearth more.  After all were dug, I gave them a light rinse from the hose but not a scrub.  You don’t want to remove too much protective waxes from the root.  Now, they have been sitting outside for a week elevated to protect from hungry rodents.  This practice helps the wounds heal over.  In the next day or so, I’ll move them inside.  The small ones I’ll keep for next year, and the big ones I’ll eat.  

Thar she blows! You know you’ve got something under the ground when you see the soil around the stem bulged up.

The swollen roots of ‘O’Henry’ sweet potato. Getting them out all still attached to the plant is an art in produce transportation.

My table runneth over with sweet potatoes. ‘Beauregard’ on the left and ‘O’Henry’ on the right.

And, oh will I eat them!  I’m ecstatic about our harvest this year.  ‘Beauregard’ is an old favorite of mine so I’m thrilled to have a good supply of this orange fleshed variety, and ‘O’Henry’ is supposedly a white-fleshed mutation of ‘Beauregard’.  It’s yield was about 50% more than the ol’ Beau.  So, if it tastes as good, I may have found another favorite variety.

One final note as far as cooking goes.  You can enhance the sweetness of them by starting them in a cool oven.  The enzyme that converts starch to sugar has more time to act if you start them cold than if you pre-heat the oven.  Cause if you’re going to grow sweet potatoes, why not make them as sweet as can be?