Thinning Might Hurt You, But it Helps Your Crops

Your garden is prepped and you plant a row of carrot seeds or several cucumber seeds, just to be safe.You’re thrilled when you get a nearly 100 percent germination rate. Wow, you must be good! Or in my case, lucky. As I beam with pride, I know that the next step is to thin the seedlings. But sometimes, I fail to heed my own advice or that of horticulturalists. This year, I am trying to do a better job of thinning some of my vegetables. Baby steps…

romaine lettuce thinned
This head lettuce is lined up nicely, but it’s still a little closer together than recommended. Of course, I can cut and enjoy it anytime — before the plants get too close.

First, let’s look at the reasons why thinning helps your crops and yield, and even improves the health of flowers you start as seeds in your garden:

  • A plant can only provide so much energy to the leaves, stems and fruit. If your aim is to get as many health, juicy tomatoes as possible, then most expert gardeners recommend pruning suckers from indeterminate, or vining, tomatoes. We often trim a few lower branches too, especially if they’re touching the ground.
  • The same goes for some fruit trees, though I’ve seen some advice that says not to bother too much with thinning unless it’s obvious that a small branch can’t handle the number of budding apples or pears. And clearly, a home gardener is probably safer letting nature and birds take care of thinning out fruit from upper branches! We chose not to thin our cherry tree and it handled the fruit just fine. The birds helped out more than I would have liked, but there were several bunches of six or more cherries on one spur and most of the tree’s fruit ripened fine.
sour cherries on tree
These cherries were nearly ready to pick and growing fine in a large bunch.
  • With vegetables planted in groups or rows, such as carrots or lettuce, thinning is more to avoid overcrowding. The plants’ roots need space to grow underground – especially true of root vegetables. If crowded, the roots might not support full, healthy growth. And above ground, the leaves need air circulation and sun. Crowded plants hide bugs and hold water on their leaves. It’s like being squashed up in bleachers at a baseball game. Aren’t you more comfortable sitting out on the grass (or in one of those chairs with a cupholder), with the wind blowing through your hair?
carrots in container
I had to do a second thinning on the carrots in this container. They are way too crowded.
Thinning carrots in container
OK, still closer than the recommended two inches in a few spots, but closer. I’ll add a few of the tiny ones pulled up to my next salad.
  • I’ll add another reason to thin that I can more easily relate to. If I feel like pulling up seedlings that made it is wasteful, I have to look at continually watering seedlings I eventually have to thin out – or even worse, plants that grow to nearly mature height and then need pulling up because of a disease or just provide a low yield – as wasting water. It’s not right to let that plant continue soaking up water that could be put to better use.
green bean seedlings
These green bean seedlings are just about right. They can be four to six inches apart, since most of the growth — and the beans — vine up above the plant.

So, what can you do with seedlings so that you don’t feel like you’re wasting a viable plant, small as it may be? The little survivor, that broke through the soil and bore leaves? If the flower or vegetable is one that transplants well, you can move it to another spot, or try it in a container. Lettuce seedlings and carrot seedlings from a second thinning are often large enough to eat, even if they’re mostly garnish on your salad.

Of course, you can also compost the plants you thin and leaves or suckers you prune. When thinning, take care not to pull up the root of an adjacent plant. It helps to thin when the soil is damp and to avoid procrastinating until plants are large and closer together.

Water Under, Not Over, a Plant

For water conservation and plant health, the smartest xeric strategy is to water the roots of the plant and avoid watering the plant’s leaves.

Let’s look at the water savings first: Water evaporates when exposed to air, and occurs at the water surface area. The smaller a drop of water, the higher the percentage of the drop’s surface area. Add the effect of wind on tiny drops of water from sprinklers and you might as well just pour that water down the drain. And if you irrigate a plant from above or with sprinklers and spray emitters, much of the water lands on the leaves, where it can evaporate. In fact, water constantly evaporates from a plant’s leaves as it is, in a process called transpiration. It’s a plant’s natural way of cooling off on hot summer days.

herb garden drip irrigation
Cascading or spraying water is for fountains and lawns, not for plants. Note at least three inconspicuous, but efficient, drip emitters in this herb garden.

Feed a plant’s roots

It’s much better for a plant to take new water in through the plant’s roots, where the water picks up soil nutrients and works its way up the trunk and stems back to the leaves to do its cooling and feeding work. There’s another reason not to spray water on plant leaves, especially late in the day or during cloudy, humid weather: wet leaves can harm many plants.

Fungal diseases such as powdery mildew on roses or apple scab on apple trees and crabapples is partly a result of water on the leaves. Sometimes, there is nothing a gardener can do. We have an old apple tree with some scab that likely came from spores in old leaves left on the ground and a week or more of cool, cloudy and humid weather in late spring.

apple scab on leaves
We don’t water this old tree near the river, but an unusually cool and damp late spring caused this brown spotting, which I believe is apple scab. It was worse on lower leaves on the northeast side of the tree, but seems to have stopped progressing. And the apples don’t look too bad!

Change how you irrigate

Often, simply changing irrigation practices can improve a plant’s health. When we first moved to a home in Albuquerque many years ago, the previous owner had installed sprayheads in all of the flowerbeds. We eventually had to replace all of them with bubblers and rework the plantings. Bubblers or drip irrigation might have required a little more planning, better leveling of the soil and more parts or emitters. But in the end, the homeowner would have saved money on his water bill and I bet on plants! Farmers know this is the way to go, and many are learning new ways to improve irrigation techniques to reduce water use.

subsurface drip irrigation
A micro subsurface drip irrigation system was used in this demonstration project in Texas. Click on the image, which is courtesy of the U.S. Department of Agriculture, to learn more about the project.

We recently visited a nursery in search of tomato cages and noted that the tomato plants they still had in stock looked awful, even though they had a few large fruits on the plants. I thought at first it was too shaded in the greenhouse, but then Tim noticed the cause: an overhead spray watering system. The leaves were spotted and nearly goldish-brown in color. I don’t know how they are healthy enough to continue feeding the plants. Granted, these plants have been in the greenhouse way past the typical time, and there are many more than you would have to deal with in your garden. Still, it seems to me they would sell more tomato plants if they watered differently.

rose water pail
Roses are especially vulnerable to powdery mildew and need deep watering at the roots. The only time I spray roses is to rid them of aphids. I use a fairly strong water spray early on a sunny day.

And in case I haven’t convinced you, here’s yet another reason to water with drip emitters or by hand near the roots of a plant instead of broadcast or spray irrigation: weeds. When you spray water, you water everything around, including weed seeds. Watering only around your vegetables’ or ornamentals’ roots confines weed growth, making it easier to pick small weeds out by hand.

hose watering tomato
It takes more time to water my vegetable garden by hand, but the hose from our rain barrel waters the plants deeply and just at the roots while I weed.

As I said before, you can’t control rain, which obviously comes from overhead. But keeping plants exposed to proper sun, trimmed and cleared to give them sun and airflow and cleaning out debris from around the bottom of trees and plants can help reduce risk of fungal diseases. Choose mulches carefully, depending on local recommendations for a given plant.

Xeric Gardening Strategy: Saving Arid-Adapted Native Seeds

Across the nation and world, efforts are underway to save native seeds. For a number of reasons, seed banks or vaults have cropped up around the globe, some located underground, to store a variety of crop seeds. Some banks store seeds in the event of an apocalyptic event, even a natural one, that wipes out vegetation. Other reasons are simply to preserve the biodiversity of crops so they can continue to adapt to changing climate and conditions and to maintain the integrity of ancient, heirloom varieties during an age of hybridization and genetic modification.

There are more than 1,000 seed banks around the world, some private and some public. The U.S. government operates one in Fort Collins, Colo. In this and most seed storage facilities, the seeds are kept in cold storage, where they can survive for decades.

seeds in storage bank
Seeds in cold storage room at Native Seeds/SEARCH in Tucson.

In various seed banks are hundreds of thousands of plant species, some of which already face endangered status. Plants’ adaptation to various climates and conditions is important. For example, native plants I mention in my posts that have adapted to low water or drought probably wouldn’t survive in a tropical rainforest. On the other hand, only plants adapted to xeric conditions thrive during drought.

A few years ago, I had the privilege of visiting the Native Seeds/SEARCH seed conservation site in Tucson, Ariz. The program was started in 1983 as a way to help improve food security for the Tohono O’odham Nation, and has grown into an outstanding program that is helping conserve the biodiversity of arid native Southwestern crops.

ancient Native American corn
Ancient Native American corn grown in demonstration area at Native Seeds/SEARCH.

I got to see inside a preservation area, hear about the program and see evidence of some of the rare or endangered plants that Native Seeds has helped preserve. This past week, Native Seeds announced an initiative that allows supporters to “Adopt a Crop,” which helps pay to get seeds planted back in the ground. The program operates a conservation farm in Patagonia, Ariz., near the Arizona/Mexico border and sells many of the native seeds from their Tucson site and online. Many seed banks also provide education programs on how gardeners and farmers can harvest and preserve their own seeds.

native seeds
Buying and planting native, heirloom seeds supports preservation efforts.

Help Plants Beat the Summer Heat

It’s hot here. I thought I would never say that. And sure, it’s not as hot as Phoenix, but even mountain communities in the Southwest can warm up in summer months. When the temperatures hit the 90s, the humidity stays below 25 percent, and the winds never subside, vegetables and ornamental plants get stressed.

columbine northeastern exposure
In May, this columbine was blooming and healthy! It’s a little stressed now. Columbines grow naturally under the shade of trees, and they need deep water as temperatures rise into the 70s and higher. We mulched around the plant and put it in a northeast-facing location to help it survive summer.

Often, our first reaction is to throw more water on a plant. Sometimes, that’s what they need. Wind, sun and heat dry plants more quickly. Native xeric plants are adapted to take some of the parching sun and wind, and sometimes a gardener can overwater a plant. Here are a few tips to keep xeric plants cool, healthy and happy during the heat of summer:

  • Start with the right plant for the right spot. That means not only a native selection, but choosing sun vs. shade or the right drainage. Most xeric plants can take plenty of sun, but some need partial shade. And most don’t take kindly to wet feet, or roots that fail to dry between watering. Wet feet can happen with overwatering or if you place lavender in poorly draining soil at the bottom of a hill, or hide it under a bush that grows quickly and shades it within a year. You also can plan ahead to take advantage of shade. It’s getting too hot for my lettuce, but we’ll plant some more north of the fence holding the pole beans as soon as they get a little taller.
garden plan for shade
The sun is so bright, it’s reflecting off the spot where we hope to get some shade for lettuce and spinach. You can see the bean seedlings on the other side of the foreground fence shadow.
  • Follow the sun. When you plant in spring, the sun and shade patterns are different than they will be in mid-July and August. So keep in mind the sun’s direction and any plants or structures that might help shade a plant late in the day, when the sun’s rays are their hottest. Remember that deciduous trees might be nearly bare when you plant, but loaded by mid-June.
  • When helping a new plant get established, the typical care instructions might not apply. The plant goes into a sort of shock, much like when you recover from illness or injury. All plants need a little more water, as well as extra sun and wind protection until established. We’ve often used portable lawn chairs to provide filtered shade over new plantings in the afternoon. Old sheets or landscape fabric also work.
  • Use containers. If you have a plant that’s more susceptible to heat stress, place it in a container. You can move it around throughout the summer based on the sun’s path. Of course, if you really love the plant and have lots of time on your hands (and wheels under a larger container), you can move it around during the day, giving it morning sun and afternoon shade.

    tomato in container
    The tomato seedlings I planted in containers are doing better than many in the ground. The patio and house warmed them up during cool nights, but provide shade now on hot afternoons.
  • Water in the morning. It’s tough to find time before work, but watering early in the day loads your plant up, preparing it for the heat. And try to keep soil evenly moist. If you have a slow drip system, the irrigation can run while you get ready for work. Cover the drip hose with a nice, thick layer of mulch and the mulch will slow the water’s evaporation and help keep the ground cool. And as I’ve said before, it’s good to keep an eye on tomatoes and other vegetables and to have someone care for them if you leave town. Once the fruit sets, you can’t drown the tomato to make up for a few days of heat and underwatering. They’ll punish you.

Finally, drink some iced tea, flavored with a small bit of fresh mint. Oh, wait, that’s for me…

Growing Edibles in Containers

Growing an edible garden makes great sense – you use water to produce food, and it’s food that can’t get any fresher or more local! Growing food in pots and other containers can be even more rewarding, especially for gardeners who have limited space, problems with critters or who want their herbs and vegetables close at hand.

lettuce and tomatillo plants in containers
Lettuce is a great container plant. The one in the foreground had tomatillos, just for fun, not so much for yield.

Rosemary, basil, lettuce and cherry or grape tomatoes are my favorite edibles to have right near my kitchen door. But I’ve been known to push the boundaries a little, once growing an okra plant in a small container (admittedly mostly for the flower) and a large pot of carrots last year. We’re upping the ante with an even bigger carrot crop, but more on that in a future post…

carrots
Here’s our dancing carrot, or rather two carrots, grown in crowded container conditions last year.

Here’s the thing – containers can take a little more water during hot summer months, but you also can confine your crop, so to speak. I believe that container-grown edibles are less susceptible to some bugs and soil-borne problems. And I love that I can move the containers to control sun exposure as the conditions change. Most of all, you just can’t beat the convenience of herbs and vegetables just outside your kitchen door at meal times.

Here are a few tips for making your container edibles fun and productive:

  • First, it can be tempting to fill your containers with soil from your garden. Resist the temptation and spend the money on some good commercial potting mix. I use organic composts and potting mixes. The reason? Ground soil compacts when confined to a pot. This makes it harder for water to drain and for roots to grow.
  • Choose your container to fit the plant’s mature size. It might look less attractive at first, but the reward of juicy tomatoes is worth your patience!
grape tomato in container
This yellow grape tomato was great for snacking right on the patio all summer.
  • If the container is particularly large, you can line the bottom with pebbles or plastic bottles to encourage drainage and use some yard or garden soil for fill. But keep it to a minimum, and make sure the soil that the plant’s roots touch is the best possible mix.
  • A few herbs are grown better in containers for their own special reasons. I like to have a small basil or rosemary on my patio table throughout the summer for the appearance, scent and convenience. And then there is mint – which should only grow in containers unless you really love it and want to replace everything else in your lawn, your neighbor’s lawn, your town… with mint. And it comes in lemon, orange or chocolate varieties to enjoy on the patio or balcony.
  • Many container-grown plants require fertilizer because the soil doesn’t have the same natural nutrients as garden soil. But use it judiciously and according to the individual plant. For example, chile peppers typically need no fertilizer. If you start with healthy soil, you need less, and if you use it too often or at the wrong time, you’ll force more growth into the foliage and get a plant that outgrows your container and gets too lanky to support its fruit.
  • Usually, you have to water container-grown plants more often, but not always. Don’t assume that when a plant wilts, lack of water is the cause. And that’s the beauty of containers – try moving the plant to the shade on hot days, or move all of them there if you have to be away for the weekend. They’ll survive better on your pre-departure watering until you return.
  • Remember that you can add mulch to containers, just as you do in flower beds. Decorative mulch can offset the look of an edible in a container, such as crushed seashells under chard. Mulch also serves a practical purpose. Those white seashells or pebbles can reflect sun back up to your potted lavender or bark chips can hold moisture in to conserve water and keep plants cool.

And if you love being creative and repurposing, go ahead and push the limits. You might end up with lower productivity from your edible, or need more total containers, but it’s fun to place edibles in a few fun or funky containers. If I want more yield, I duplicate the seeds or transplant in the ground or a larger container. That way, I get the aesthetic pleasure and practical returns.

spinach in metal container
We found this old metal bucket at my in-laws’ ranch and planted some spinach in it.

Harden Off Seedlings Before Planting

When you head out to your garden on a chilly morning, it takes you some time to acclimate to the weather. After you’ve done some digging or weeding for 15 minutes or so, you might peel off a layer of clothing as your body warms up. The outside temperature probably didn’t change much in 15 minutes, but your body adapted to your surroundings and even toughened up to take them as your blood pumped into muscles and your heart rate rose.

tomato seedling
Short-season tomato seedling growing in starter soil.

Your tomato and other vegetable and herb seedlings need the same sort of acclimation before you take them from under your grow light, from a greenhouse, or from the comfort of their commercial nursery home. Give them a little bit of time to adapt to their new outside location. It’s called “hardening off,” and here are a few tips:

  • Take a minimum of a few days when you can, and ideally up to a week, to harden off seedlings. Count backward from your planting date – usually your average last day of frost – and start hardening off seedlings about eight days before that date.
  • Ease your plants into their new environment. That means it’s not a good idea to take them from a greenhouse from dawn to dusk the first day. Start with a few hours of outdoor time and gradually increase it each day. Cut the time short if the wind really picks up.
  • Speaking of wind – and sun – keep your plants in a fairly protected location. Start by putting them out mostly shade the first day and moving them every few days to gradually increase their sun exposure. You may need to protect them from critters, too, so consider local bunnies or other munchers if they often visit the area where you set out the seedlings and place them up on a table.
Seedlings and cuttings hardening off
Tomato seedlings and sage cutting hardening off under the shade of a glass patio table. The table offers some shade and wind protection.
  • Gradually increase time spent out late in the day as well. Your plants need to learn to spend the night outside, but don’t leave them out the first few nights. And be sure to bring them inside if there is any chance of freeze. On the first night out, try to put them in a well-protected location where they won’t get too much wind and receive a little warmth from your home or a south-facing wall.

Finally, cut back on watering as you begin hardening off the plants. They also need to learn to toughen up before transplanting. Of course, once you plant them, water a little extra until established, then water consistently per the plant’s needs.

bell pepper seedling
Bell pepper seedlings need to harden off and toughen up before the soil and daytime temperatures are hot enough for us to plant them.

Growing Short-Season Vegetables

I want a greenhouse. But want and have are too far apart right now. And the beginning and end of our growing season are too close together. Like many gardeners, we want to produce as many edibles as we can during our growing season. And like many rural residents, we crave affordable, fresh produce.

We’re better off than some; our last freeze occurs in early to mid-May, and our first freeze in early to mid-October. But we all know how those predictions go. With cool, high-desert evenings, the ground has to warm up enough to germinate seeds. Add high winds and low humidity, and it’s pretty much trial and error from one year to the next!

Here are a few tips for growing vegetables and other edibles in short seasons from our attempts and courtesy of the Pacific Northwest Extension services:

  • Make sure your garden is prepped and ready for planting as soon as it’s warm enough to do so. I wrote about spring preparation a few weeks ago.
  • Choose the best spot for your garden or raised bed based on microclimates, such as along a south-facing wall to maximize heat, or where you have a natural wind break in your yard.
  • Speaking of raised beds – they warm more quickly than the ground soil. They also can drain better, but may dry faster. So consider all of these factors when selecting plants for raised beds and containers.
grape-tomato-in-pot
This yellow grape tomato grew in a container against a south wall on our patio last year. They were delicious!
  • Start your seeds early enough to have nice, sturdy transplants ready. Naturally, that only works for those edibles that transplant well, such as tomatoes. If they become too big for the starter pot, transplant the entire block into a larger pot of sterile potting mix until ready to go in the ground. And be sure to harden them off for a few weeks before planting.
  • Cool-season vegetables are easier to sow in colder climates. Examples are beets, Brussels sprouts, carrots and several greens. I’ve already planted spinach, arugula and several loose-leaf lettuces in containers and in our garden.
  • Warm-season crops might need a boost, and they surely need a good start. Make sure to plant beans, melons, tomatoes, squash and cucumber after the soil temperature reaches 50 degrees. Covering them with a light, white landscape cloth can help protect them from cool night temperature and gives seedlings a fighting chance against flying and hopping insects.
  • Choose early bloomers. Some varieties mature earlier or have a shorter time to harvest. Tim really wants honeydew, which should be sowed directly in the ground after the 50-degree soil mark. We found a hybrid that says it can be harvested in 70 days, so we’re going to give it a try. If it doesn’t work, we’re only out the cost of a seed packet, the time and most importantly, the water. Look for terms such as “cold climates,” “short season,” “early to mature” or “northern gardens.”
short-season-bell-pepper
The North Star Bell Pepper is an early-maturing pepper variety, a must for gardeners in cooler climates. Image courtesy of HomeFarmer (www.HomeFarmer.com)
  • Help your plants stay warm (or shaded) with an appropriate cover. Aside from row covers, you can use tires or hot caps to protect and warm young plants. Our neighbor is in the stucco business, and he has given us dozens of five-gallon buckets. My husband cuts out the bottom and they work great at protecting young plants from sun and wind.
protect-vegetable-seedlings
Recycled buckets from our neighbor protected young seedlings in last year’s garden.
  • Of course, here in the dry Southwest, we create troughs or wells for nearly every crop to ensure consistent, deep watering and good growth.

Finally, it’s great to get advice from local “experts.” Most are just trying to be helpful. But don’t let lore and legend trump your can-do attitude and willingness to try these tips and your own brilliant ideas!

Spring Garden Preparation

I am itching. Well, it’s spring-time in New Mexico, so allergies have made my eyes itch. But in the figurative sense, I am itching to get my vegetable garden started. There just isn’t much we can do with the short season here, but we can prep our garden.

Our fall “to-do list” included weeding and cleaning up our garden. Did we get to it? Nope. So about a month ago, we headed outside on a warm weekend with our garden hoes and set to work. We dug up and hauled off all of the grass, weeds and debris, partially leveled the garden and mixed in about 10 bags of organic topsoil/compost. Then, we covered it all with a layer of black landscape fabric hoping to “cook” the compost and kill any remaining weeds or seed. Then we bolted the fabric down any way we could to keep the wind from blowing it away.

 

garden-preparation
After weeding, we added compost and covered the dirt. We anchored the fabric with dirt and rocks.

 

Next up? Discussing this year’s plan. Most important is crop rotation. We want more space to move around and more space for a few of the plants. We also want to eliminate waste. So we cut back on the number of crops we’ll grow, move a few others to patio containers, and add one raised bed (in a watering trough). Crop rotation is critical for plant health and yield. We ordered seeds for the vegetables we most enjoy to reduce waste and looked for the shortest time to harvest on those that have the most trouble in our cooler climate.

vegetables-from-garden
A pick from last year’s garden. We’ll skip the broccoli and peppers this year but plant more beans, which freeze well.

The seeds are in, so the next step will be planting seedlings. We’ve got our starter pods and two heating mats. We’ll start the seeds in a few weeks, hoping they are just right for setting out after our last frost date (around May 10 to 15). Meanwhile, I’m watching for a nice, warm day so I can prepare a few containers for lettuce, arugula and spinach seeds. I’m willing to try them as soon as possible because nothing beats walking out my back door at lunch time and cutting fresh leaves for a salad!