CO-Horts Blog

Monday, March 30, 2020

Illuminating indoor gardens

Posted by: John Stolzle, Jefferson County Extension 

One of the great challenges I’ve faced with my indoor garden is light, or rather the lack thereof. At times, I view my indoor garden as low productivity time sink; but at other times I've noticed that it can be pretty fun to have such a variety of plants to tinker with and train from the comfort of home. An indoor garden can offer (a few) fresh tomatoes and herbs, and green colors in the middle of winter. And personally, in my apartment, in the middle of a city, I definitely enjoy the extra connection with nature that it brings.
My indoor garden is often a disorganized mess of green. On the bright side, I am able to harvest a few small bunches of cherry tomatoes every month.

When plants don’t receive adequate light, they become more susceptible to disease, their leaves can become pale and discolored, some will even drop leaves which further reduces their ability to absorb light. This low-light leaf drop feedback loop has resulted in the failure of many of my indoor plant experiments. Light intensity also plays an important role in a plant’s production of lignin, a scaffold-like component which plants produce to support themselves. Without proper light, many plants will often flop over due to weak structural support. Twine, twist-ties, or string can be used to help support a weak plant. 

This 'Purple Passion' (Gynura aurantiaca) bolted earlier in the spring. Using some twine and makeshift stakes, it has now become a 'spiraled' purple passion.
Compounding the issue of inadequate support structures, many plants can exhibit strong shade avoidance mechanisms. These mechanisms often manifest in a plant putting more energy towards the development of fast-growing elongated shoots and can result in spindly or “leggy” plants. The Purple Passion in the image above, for example, bolted and grew many inches within a just few weeks.

Increasing light (or PAR - photosynthetically active radiation) to adequate levels for a given plant can resolve these issuesGrow lights can be used to accomplish this or to mitigate the effects of low light conditions.

Even with these lights, the plants in my garden do not receive as much light as they would if they were planted outdoors. The lights just help mitigate some of the problem. 

Light Types:
Many options such as LEDs and fluorescents are available for homeowners to purchase. Decisions regarding 'which light is best' should be based upon individual situations, and factors such as the needs of the plant, energy consumption, heat, quantity of ambient light, and position of the to-be-installed grow light in relation to the plants. Below, I have provided links to pages which discuss these topics in more detail: 
A few last minute tips:
  • Help the plants support themselves. A small trellis, cage, or other structure can give the plants something to climb on.
  • It is very easy to overwater indoor plans. A general recommendation is to only water when the top 1-2 inches (2-5cm) of soil are dry. 
  • Scan with some regularity for pests and disease. Indoor plants often face significant challenges regarding pest infestations (especially of spider mites & aphids) due to a lack of natural predators that could otherwise help keep pest populations in check. Catching a problem early on can save lots of headache and potentially prevent the loss of a plant.
If you are interested in indoor gardening, you may appreciate these other posts in this indoor blog series: 

Friday, March 27, 2020

To the garden I go: (Gardening and Mental Health during COVID-19)

By: Emily Jack-Scott, Colorado Master Gardener

And so, to the garden I go.

I know it’s likely too early to plant in the high country, but I can’t go volunteer at my beloved school greenhouse because all school facilities are closed (I wish I could at least plant a cover crop in all the beds there before this period of fallow!). So I’m pretending that it’s officially 4-6 weeks before average last frost in the high country of Colorado, and I planted those parsnip, sugar snap pea, spinach, leek, and rutabaga seeds in the ground. Maybe last frost will be early this year. Or maybe the seedlings will all freeze. Or maybe they’ll find enough insulation from the surrounding leaf mulch to grow as they shelter in place. In the face of the trajectory of the COVID-19 pandemic, my gamble to plant seeds early barely registers as a risk. All I know is that planting those seeds brought me purpose, familiarity, and hope – highly coveted aspirations in these times.

 My impulse to be in the garden right now is well-supported by research on mental wellness. As hundreds of scientific papers (and countless hours of experience) have demonstrated, gardens are a space where we can practice acceptance, accelerate healing, develop a mindset for growth and learning, reduce stress and connect with our world. And in the midst of these times, prioritizing mental wellness is absolutely critical.

 After all, these times are uncertain, if not devastating, for so many of us. Don’t misunderstand me – I’m a firm believer in resilience (I just planted seeds in March in the high country of Colorado after all). But it’s important for us to acknowledge the grief we rightfully harbor. Grief for lost livelihoods and a sense of routine if not security. For the well-being of those who were already so isolated by age, ability, or mental illness. For those who do still have jobs, but no childcare, and are now working before the kids wake up, and during naps, and after they go to sleep. For those who ‘stay at home’ with an abusive partner or family member. For those most valuable essential employees shouldering Atlas’s load to keep the ship steady. For the overburdened community leaders and organizations who are striving day in and day out to meet community needs. For the medical professionals putting their commitment to community above their own comfort and safety. For those near and far that are navigating this difficult time together.

Gardening at the Jack-Scott household. 
And so, to the garden I go. My toddler puts on his bright yellow rain boots, and I show him how to plant seeds. He’s two years old, a “big kid,” and I can already see that he has inherited the green thumb that has passed through my family for generations. He doesn’t know it yet, and I didn’t until just recently, but we’re the product of generations of farmers and orchardists. It makes sense now that even though I grew up in the heart of an urban area, that I became an arborist and a devout gardener; like my mother, like my grandfather, and his before, and on and on. Or maybe, my son’s green thumb is the result of me hauling him with me to volunteer at community gardens since before he could talk. 

 Either way, I watch as he spies the first bee of the season, caked in pollen from our crocuses that bloomed not a day before. And right next to it, a moth out in the full sun of day, eagerly drinking the nectar of a tiny iris. My son reaches his tiny forefinger out to the moth and very gently (more gently than I thought a two year old capable of), he prods it and watches it bounce to the next bloom. He whips his face to me beaming as bright as the blue sky sun. A couple feet away we notice a pollinating fly, bouncing from crocus to crocus. The bounty of life supported by our meager handful or early springtime blooms is inspiring, and a welcome reminder of the gritty resilience we embody as creatures of nature.

This pandemic is a stark reminder that, as successful a species as we are, we are still governed by our naturalness. And this unpredictable season of late winter/early spring further drives the lesson home. This is our early spring freeze. But these days of cold and isolation are spliced with days of warmth and awakening. In reaction to dire news, there are instantaneously so many people aching to act, to help – to be growers of food, of community, of family, even from within the confines of our homes. Like springtime buds aching for the chance to unfurl.

Crocus blooms (Photo: Emily Jack-Scott)
This instinct is our natural resilience. And perhaps you, like me, find deep connection with it while in the garden with dirt under your fingernails, or a pair of pruning shears in your too-often-washed hands. So I encourage you to go to the garden. As others have highlighted in recent posts including The Gift of Gardening, The Basics of Fruit Tree Pruning, and Gardening for the Home Team, there are a multitude of valuable springtime gardening activities that are ideal for this time of year. Sow cool season vegetable seeds in the ground. Transplant fruit trees, shade trees, and shrubs while they still wait in dormancy. Grow starts for yourself, your neighbors, and for the community gardens that will be playing catch up when this freeze thaws.

This is our calling. And so, to the garden we go.

Additional resources:

Gillihan. 2019. 10 Mental Health Benefits of Gardening.

Poplett. 2018. Horticultural Healing: Plants and Mental Health.

Wood et al. 2016. A case–control study of the health and well-being benefits of allotment gardening.

Van Lier et al. 2016. Home Gardening and the Health and Well-Being of Adolescents.

Wednesday, March 18, 2020

The Gift of Gardening

Posted by: Deryn Davidson, CSU Extension Boulder County

It is no secret that time spent in the garden has myriad benefits to our health and well-being. It can provide stress relief, mental clarity and moderate (or depending on the task at hand, intense) physical activity. This holds true under normal circumstances and it may prove to be even more important during this time of uncertainty as we all learn to navigate the new reality of social distancing and COVID-19. An experiment published in the Journal of Health Psychology looked at gardening versus reading as stress-relieving activities. The study found that both reading and gardening decreased stress, however, the decreases were significantly stronger in the gardening group. In the coming weeks as public events are being cancelled and gathering spaces are being closed, people will be looking for a multitude of activities to pass the time. For me, it’s a comfort to know that we can still get outside to connect with nature.

Now, given that this is springtime in Colorado and it is quite possible, quite likely in fact, that we will still get at least one or two good snow storms along with plummeting temperatures, what are our gardening options?? It’s a great time to tackle those winter annual weeds. Since we’ve been getting moisture here and there, it is easy to pull them up by hand. These are plants that germinate in the fall and winter and grow actively in the spring. They are the ones that seem to pop-up overnight and create a carpet of green in your garden. After they bloom in the spring, they will drop their seeds and die. The trick is getting them out of the ground before they set seed which will germinate the following fall or winter. A few of our more common winter annual weeds are prickly lettuce, henbit, cheatgrass, redstem filaree and any of the mustards (e.g., blue, flixweed). Spring pruning should be on your list too. If you have fruit trees that need to be pruned, now is the time to get that task done while they are still dormant. Pruning fruit trees is different than pruning shade trees and there are great CSU Extension resources online to guide you through that process (including the very informative blog post just before this one!). You can also prune shrubs that flower in the summer or fall. If you prune spring blooming shrubs now, such as lilac, you will prune off those buds so pay close attention to the bloom time of your plants. If you have a vegetable garden, you can be planting peas, spinach and other cool-season crops. You can also take some of your gardening inside and get seeds started for those warm-season crops like tomatoes, squash and melons.

Photos taken one day apart in spring 2017
Now, what if you don’t have a garden? Or what do you do when the inevitable spring snow hits? While it’s not quite the same, there are online resources to take advantage of. Many public gardens are closed to the public right now, but they are staying connected with visitors virtually. Check out your favorite local or even international botanic gardens on their websites, FaceBook and Instagram accounts. You can peruse photos of their gardens and daydream about warmer days to come. Another great option if you can’t get into the garden is paying attention to your houseplants. Check them for insect pests, clean-up old leaves and give them a little extra attention. By working with your houseplants, you will still reap some of the same benefits as going outside.

Gardening is a simple, and meaningful way to connect with the larger world around you. The opportunity to commune with the plants, bees, birds, and other animals that are benefiting from your efforts is truly a gift that I hope will benefit you over the coming weeks, months and years.

Wednesday, March 11, 2020

The Basics of Fruit Tree Pruning

By Amy Lentz – Weld County CSU Extension

The season for pruning fruit trees has been in full swing lately. My colleagues and I have been busy teaching classes, talking with the public and helping growers “get their fruit tree pruning on”. It can be an intimidating task for some - "What if I prune out too much?" or "What types of cuts should I make?" With a little extra patience, basic research and confidence, you can do it...I promise.

Weld CMG's helping teach residents of a community.
Larimer CMG's learning to prune.

Here are some questions and answers that might help you get started (or finished) with your pruning needs.

1. Are fruit trees different than shade trees?

Yes! Fruit trees are pruned differently than shade trees. With fruit trees, you are growing a crop, maybe even for monetary gain. Therefore, you will be manipulating the tree’s growth more than you would when pruning shade trees. The three D’s (disease, damage and dead wood) still apply, but you will also be making cuts for other reasons, such as to increase fruit production or to fill an empty space with more branches. When trying to decide what to prune and what to not prune, look for strong branches with wide branch angles, which are more capable of holding a heavy load. You want to keep those! It's better to remove branches that have a very narrow, or weak, branch angle. Also, you would not be pruning your shade trees as often or as heavily as you would fruit tree! 

2. How should I prune a young tree vs. an older tree?

Young  fruit trees are much more forgiving than older fruit trees, so go lightly if you are pruning an older tree that needs a good deal of thinning. Spread out your pruning cuts to open up the canopy by pruning it lightly over several years. You can prune your young trees (say up to 5 years old or so) a little harder - and they are easier to train when they are young. So start with young trees if possible. Here is an example of how to train a tree over 5 growing seasons from a one year old whip (spreaders were added after the 4th spring):

3.  How do I know where the fruit will be?

Most fruit trees often bloom on old wood. Apples and pears, for example, grow on spurs which can begin developing after 2 years and last a long time, up to 20 years. Plums and cherries also have fruiting buds that occur on old wood, at least 2 years old, either on spurs or along the stems. Peaches, on the other hand, are developing fruit buds on last years growth, so annual pruning to encourage new growth is important for peaches. It's important to know the difference between fruiting buds and vegetative buds. You will be removing some fruiting wood during the regular pruning process, but you don’t want to inadvertently prune off all those little spurs, which will lead to fruit during the upcoming season.

Photos from University of Maine Cooperative Extension:
4.. When is the best time to prune my fruit trees?

With the warmth of spring happening more often lately, it’s time to get outside and finish up those pruning jobs if you haven’t already. The best time to prune is in late winter or early spring when the trees are still dormant (which is hard to judge in Colorado!). Either way, you want to stop pruning when the buds first begin to swell and break. It’s best to prune older trees first to make sure they have enough time to heal before spring and leave the younger trees until later in the pruning season. 

Another reason we prune when the trees are dormant is to reduce the spread of diseases like fire blight, that affects those fruit trees in the Rose Family, such as apples and pears. This particular disease can easily be identified and pruned out in the winter. 

For more information on Fireblight, see the following fact sheet from CSU:
Another good source of information on fireblight, more for the commercial orchard, can be found here from Washington State University:

5. What are my goals and objectives when pruning fruit trees? 

Approx. 5 year old cherry trees after pruning to thin the canopy.
Your main goal when pruning fruit trees is to open up the canopy of the tree to allow increased light penetration and increased air movement in the center of the canopy, where fruit spurs are located. 

You want to encourage outward growth on the tree to get branches to grow into open space. This is done by pruning to an outward facing branch or bud. Along with the three D’s (diseased, dead or damaged), look for crossing branches, branches that are shading or crowding one another and branches pointing back toward the tree. Don’t remove more than 25% a single pruning season, less for older trees so you don’t stress the tree too much. This will help with fruit development, as well as, decreasing the prevalence of insects and disease. 

To do this, remove crowded branches by making reduction or thinning cuts back to branches that are facing outward, away from the trunk. Reserve heading cuts (where you cut back to a small bud) for only those branches where you want to encourage new growth, such as lower branches or young branches. As you remove some of the twigs and branches to allow for more space in the tree, you will also, in effect, be reducing the number of fruit buds on the tree as you remove wood, so you will also be increasing the energy allotted to the fruit buds that remain – creating larger fruits that have ample sun and lots of space around them. This is the goal of growing fruit trees!

Finally...How can I build my confidence to prune my fruit tree?

Pruning fruit trees takes time, patience and a little critical thinking. A hands-on approach helps a great deal to make these concepts sink in. Definitely look beyond this blog because there is a lot more information than what I could provide here. When doing your research, be sure to look toward education- or research-based information and watch videos to help you make sound decisions when pruning. You can always remove a branch…but you can’t put it back on! Take your time, think about the branches you want to remove and what you want to keep. You can do it!

For more information on pruning fruit trees, check out the following sources from Colorado State and other universities:

Cornell Cooperative Extension - Pruning Apple Trees

CSU Fact Sheet - Training and Pruning Fruit Trees 

Utah State - Pruning Fruit Trees: Clip with Confidence!

Educational Video Series from Montana State 

Friday, March 6, 2020

Gardening for the Home Team (Pollinators, That is)

By Sherie Caffey, CSU Extension-Pueblo County Horticulture Agent

Lately it has been pretty cold outside, but soon enough days will be getting longer, temperatures will be getting higher, and we will start to see the first signs of life from pollinators in our gardens. Of course our gardens bring us joy, but they are also very important for our native animal pollinators. Keep these creatures in mind when you are gardening and they will reward you with their presence!

Honeybees come to mind when you think of a classic pollinator. Honeybees are not natives of North America, but we do have plenty of species of native bees! Honeybees are social and live in hives, but 70% of Colorado’s native bees are solitary and nest in the ground in bare soil. We also have many species of native butterflies that we will see visiting a busy pollinator friendly garden. One of the most exciting critters to see fluttering around your flowers has to be the hummingbird. We have a few species that will pass through Colorado at some point in the year.

These native pollinators have evolved to pollinate plants that naturally occur in our area. This is why if you are trying to cater to native pollinators, it’s best to plant native plants. These plants will provide the nectar and pollen needed by our pollinator friends, and will also thrive in our area with a lot less water and maintenance. An ideal pollinator garden will have at least three species of plants blooming at all times during the growing season. Grouping individual plants of the same species together also encourages pollinators to visit and saves them the energy of flying from plant to plant. The more variety you can add; the more diverse pollinators you can attract.

Plants aren’t the only consideration you should make when planning a pollinator friendly garden. In addition to pollen and nectar, pollinators will also appreciate a water source. Fill a bird bath with clean water, and add some rocks for butterflies and bees to land on. Pollinators also need shelter, consider adding a butterfly or mason bee house, or a hummingbird feeder, and leave plenty of bare soil for ground nesting bees. Always be very cautious with your use of chemical pesticides and herbicides in areas that you hope to have pollinators visiting.

So if you are looking to add some plants to your landscape, plant for the home team pollinators! You'll have a beautiful, lively, colorful garden that works for you and our native pollinators.

Tuesday, March 3, 2020

Control of Grasshoppers

1402129 Grasshopper damage - by R J Reynolds Tobacco Company
If you are seeing holes and gnarly places chewed in your plants, it could be the result of hungry grasshoppers. Sometimes we do not really think much about grasshoppers until they become large and begin showing up everywhere. By then, it might be too late to control them.

If you live in the country, you may experience more grasshoppers than your friends in town. This is because grasshoppers prefer to lay their eggs in the fall, in dry undisturbed areas such as fields, pastures, roadsides, or empty lots. Depending on the weather, the eggs will begin to hatch in mid to late spring. 

After the nymphs are born, they begin feeding on lush green vegetation in the immediate area. As plants begin to dry up with the summer’s heat, and moisture becomes less available, food sources grow scarce and the hoppers begin moving to more desirable locations, namely your lush yard. 
Two striped Grasshopper, Linda Corwine
A female grasshopper can lay up to 400 eggs, found about ½ inch under the soil. Many of the nymphs will die before they become adults, but with that many eggs being laid it doesn’t take long for their populations to become extensive. Fortunately, there are many natural predators such as birds, nematodes, blister beetles, robber flies, skunks, and occasionally coyotes and wolf spiders to help control their populations.

While a few grasshoppers in the garden are expected, and cause no real damage, populations can become quite large taking its toll on your plants. Within 16 hours, a grasshopper can eat its own weight in green food. This is not bad if you only have a small population to deal with. It is said that if you have 7 grasshoppers per square yard over a 10-acre field, they will eat the same amount as a cow! I am not sure how much a cow eats, but I have seen plants severely damaged in a very short period.

The good news is, there’s a great organic pesticide that can help solve the problem. Nosema locustae, a fungi called Microsporidia, is mixed with wheat bran, which is a favorite treat of grasshoppers. As the unsuspecting grasshopper eats the bait, the fungus infects the hopper’s stomach, producing a chronic disease. Because this takes a while to act, patience is required. In fact, the populations may not decrease until the following season. The bait can also control earwigs (which can be considered either a beneficial or troublesome insect), cutworms, crickets, and sowbugs. It’s not harmful to mammals or beneficial insects such as bees!
Nolo Bait, Linda Corwine Photo

The Microsporidia is sold under various trade names such as Nolo Bait or Semaspore. It i commercialized by mass production in laboratories. You may have had a hard time finding Nolo Bait in previous years because there was a fire at the factory in Durango in 2018. The supplier of Semaspore put the business up for sale. However, it should be in good supply again this season. Because this is a living organism, it only has a one-year shelf life and must be stored carefully.  Homemade baits can be made, but are not safe around children and pets.

Baits will work much more effectively on young grasshoppers when applied in the evening hours, and when it’s cooler. Some grasshoppers actually prefer to feed at night, rather than during the day. Most grasshoppers will stop feeding when temperatures become too hot.

Treating the areas where the grasshoppers are hatching will give the best results, but this isn’t always possible. A barrier strip of grass, weeds, or flowers, around your property can be a good place to treat grasshoppers if chemicals are required. Just make sure that your barrier does not consist of weeds that are invasive varieties. Carbaryl, permethrin, and acephate are all effective products.

Grasshopper control is not a one-time shot with a pesticide. In spite of your best attempts, some hoppers inevitably manage to find their way to their favorite foods. Crops such as lettuce, rhubarb, tomatoes, and corn are always on the menu. Because they feed on such a large variety of plants, take time to inspect your garden and observe who’s having a hopping good time.

For additional information refer to Fact sheets 5.535 and 5.536

Linda Corwine McIntosh
Colorado Master Gardener Tri River Area, ISA Certified Arborist, Commercial Pesticide Applicator