Category Archives: Ammendments/Fertilizer

Never Put a $10 Plant in a 10¢ Hole and Other Gardening Tips From Denver Master Gardeners

planting-1898946_1920Passionate gardeners love to talk about gardening, so with that in mind, we recently asked Denver Master Gardeners for their best gardening advice. Responses included tried-and-true practices, creative suggestions and good reminders for all of us as the gardening season kicks into full gear.

As the title of this post implies, we believe that great plants come from appropriate soil preparation. Amending with compost is often imperative as soil in our region tends to lack organic matter. But proceed with caution, as some plants, such as natives, prefer a leaner, less fertile soil. Too rich soil will cause these plants to underperform and often just flop over. It pays to do a little homework before planting, read seed package directions and have your soil tested.

One of our gardeners shared her recipe for amending soil: Add 1/2 a handful of both Alaskan fish pellets and triple super phosphate to half a bucket (such as a kitty litter pail) full of compost. Mix this into the planting hole for strong root development and beautiful blossoms.

A tip borrowed from the Rock Garden Society is to plant bare root. By gently shaking off most or all of the soil that the plant is purchased in, the plant will adjust to the garden soil without the soil interface (or boundary) that can occur between two soil types. Bare root planting promotes healthy root development.

mulch-1100555_1920Mulch, mulch, mulch is the mantra of many of our survey respondents as it keeps weeds out and moisture in. Add it like crazy each time you dig in the veggie, perennial and annual gardens and don’t forget container plants too. Small to medium-sized bark chips are popular, practical and pleasing to the eye. Natural mulch options are very effective, including not quite finished compost from the compost bin which will add carbon, feed living organisms, prevent water runoff and prevent compaction. Local arborists are often willing to drop off wood chips which would otherwise fill up the landfill. In the fall, mow over your leaves and spread them throughout the yard, they’ll breakdown by spring and add organic matter to your soil. Consider purchasing a chipper to grind up branches and other garden waste.

garden-hose-413684_1920Suggestions for responsible use of water include watering when the plant needs it instead of on a set schedule. Soaker hoses, often made from recycled material, are effective for watering plants at the soil line. Plants (even xeric ones)  need moisture to maintain healthy roots and overall strength, but often less than we think. For example, the Water Smart Garden at the Denver Botanic Gardens is watered about seven times during the season.

Weeding can feel like a no-win battle, but attacking weeds after a soaking rain makes the task easier. Pull weeds and unwanted volunteer shrub and tree seedlings when they are small, before they take hold in the ground or develop seed. Add stepping stones to the garden to avoid stomping on plants and compacting soil when working in the garden.

bindweed-1207738_1920A clever tip to eliminate stubborn weeds, such as the nasty bindweed shown here, is to take a large piece of heavy cardboard, make a cut from the edge to the center. Keep the cardboard as level as possible, slip the vine in the center and spray the vine with the herbicide of your choice or horticultural vinegar, which is sold in garden centers. The cardboard will protect surrounding plants from overspray. Aggressive weeds may require multiple treatments during the season.

One of our members recommends a tomato planting technique passed on through generations of farmers. She adds blackened banana peel to the soil and feeds them with skim milk upon planting and again one month after that. This less conventional practice yields her sweet, abundant fruit. While CSU can’t vouch for the scientific efficacy of this, the banana could be adding potassium and the addition of calcium may reduce the chances of blossom end rot.

plant-1585251_1920Growing tomatoes in containers is recommended for those with limited space. Select varieties which produce smaller fruit such as Patio, Cherry or Sungold. Use a large container (18+ inches in diameter), a sturdy support and a tray with casters. This allows plants to be moved from the path of hail or to optimal conditions. Container plants of all kinds benefit from weekly feeding of 1/2 strength fertilizer.

To keep pests at bay, try a thorough weekly spray of water during the growing season, including the walls of the house and fence. It’s a kinder way to shoo pests away.

If your vines need a sturdier trellis consider building one out of remesh, which can be found at hardware stores. It makes a durable, cost-effective support and can easily be cut with bolt cutters. It also can be attached to supports to create a dog run or create plant cages.

botanical-garden-413489_1920In the flower garden, invest in perennials for texture and dimension and add annuals for bold color. “Enjoy the randomness of some plants that choose their own spots to thrive” suggests one gardener. What a positive way to think of the seedlings that sprout up at this time of the year. Remember, too, that perennials may not come into their glory until the second growing season.

Gardening is a four season hobby. Winter watering of trees and shrubs will help keep them healthy and  veggie gardeners can get a jump on the season by using a cold frame or floating row cover to get an early start on lettuce, spinach and other cool season crops. Fall is a fantastic time to fertilize, aerate and over-seed the lawn. It is also an ideal season to divide perennials so that they settle in and are ready to take off in the spring.  Share your divisions with your neighbors, too, or trade for plants you’ve admired (envied?) in their yards. If you need more gardening space, solarizing or sheet composting is an excellent technique to ready a new garden bed and can be started throughout the year.

And lastly, a veteran gardener advises us to “Remember each little garden flower or planting arrangement is a moment in time. It will change. Don’t worry about it or take it too seriously.”

 

Written by Linda McDonnell with thanks to the many Denver Master Gardeners who shared their advice.

All photos courtesy of http://www.pixabay.com, a source of royalty free images.

CSU Webinar Helps Solve Garden Mystery

Deformed tomato leavesEvery summer is different in the garden, but this year I found something I hadn’t seen before with two container tomato plants. The new leaves on these  plants was stunted and twisted into odd shapes.

Like many gardeners, I’ve seen plenty of tomato problems in my garden over the years. Early blight, late blight, blossom end rot and insect damage have cropped up from time to time, but these twisted leaves had me stumped.

I looked for images of similar problems online and checked my Tomato MD app, but I couldn’t find anything else that looked like that deformed growth.

In a great gardening coincidence while I was finishing my Colorado Master Gardener continuing education requirements, I clicked on a Small Acreage Management (SAM) webinar, and the mystery was solved.

These SAM webinars are posted on YouTube, so any gardener can watch them for free. The one that helped me diagnose my tomato plant problem is called “Herbicide Carryover and Fall Garden Care” led by Darrin Parmenter of CSU Extension in La Plata County, dated Sept. 4, 2013.

Herbicide carryover can happen when gardeners use herbicide-treated hay, straw or grass clippings as mulch or compost in their gardens. Herbicide carryover can also occur if gardeners apply manure from livestock that ate treated pasture or crops. Tomatoes and members of the tomato family are especially susceptible to herbicide carryover.

I’ve used well-aged horse manure in my garden for years and there’s never been a problem until this season. It turns out that herbicide carryover from horse manure is the top pathway because herbicides can pass through horses so quickly.

As soon as I understood the problem, I started a remediation program to improve soil microbial activity in the two containers with the affected tomato plants. I’ve cultivated the soil to increase oxygen, added a different kind of organic matter to increase beneficial soil organisms and used a home-made organic mulch. I’m also keeping the soil evenly moist and using a liquid fertilizer once a week.

According to Darrin in the webinar, the tomato plants may recover if there’s enough vegetative growth. I’m certainly going to be more thoughtful with how I amend my garden soil in the future.

By Jodi Torpey
A Colorado Master Gardener

Take a Soil Test to Start the Gardening Season

soil sampleWhen it comes to growing a garden, if a little fertilizer is good, a lot is better. Right?

Not really. Fertilizer applications should match the needs of the soil and plants. Too much fertilizer, especially applied to smaller areas, can create more problems. One proven way to avoid overfertilizing is to invest in a simple soil test. It’s a tool that gives the most accurate method to tell the fertility of a garden, lawn, field or pasture.

“It’s important to get a soil test to know how your garden will grow over the season,” says Tegan Deeney, a lab tech with CSU’s Soil, Water and Plant Testing Lab in Fort Collins.

“I tested my soil when my pumpkin plants started dying when they were only two inches tall. My soil test showed there wasn’t enough nitrogen nitrate in the soil, and there was a simple fix.” She says a lot of pumpkins grew that year after she amended the soil with the recommended nutrients.

“The earlier you test, the better. You won’t run into the issues of trying to amend the soil around plants,” she adds.

Instead of guessing what your soil needs, a routine garden and landscape soil test will give you the specifics. For the $35 fee per sample, you’ll get results on soil pH, EC (Electrical Conductivity measures the available nutrients in the soil), organic matter, nitrate, phosphorous, potassium, zinc, iron, copper, manganese, boron, lime, and texture estimates.

In 2015 CSU’s Soil Testing Lab evaluated 2700 soil samples from horticulture alone. That total doesn’t include research soils or soil samples from farmers.

A soil test uses samples collected from the yard, garden or field. Soil sample collection kits are available from CSU Extension offices or some garden centers. CSU’s Soil Lab website has soil collection forms, instructions and a list of participating garden centers. For more information contact the lab at 970-491-5061.

A typical sample uses only two cups of soil that’s a combination of 5 to 15 samples (depending on the size of the area). Here are the basic steps for collecting a sample:

1. Use a clean, rust-free trowel or spade.
2. Collect samples at a depth of 6 inches; dig straight down, not at an angle.
3. Take at least 5 samples of soil from the area and combine in a clean plastic container.
4. Remove about two cups of soil and allow to air dry.
5. Place the sample in a CSU soil container or a sandwich-size plastic bag.
6. Seal and label with name, address and location of the sample.
7. Send the sample to the testing lab.

The turnaround time for results is about two weeks. Results will be mailed to you or include an email address for a faster reply. The lab results will tell you which nutrients your garden needs or if there’s an overabundance of nutrients.

With all the time, money and effort it requires for successful planting and growing, it makes sense to invest in a simple soil test. Consider it a gardening investment, almost like buying a plant insurance policy.

By Jodi Torpey
Denver Master Gardener

Decoding Fertilizer Labels

On a recent visit to a garden center, a customer was overhead asking  about the prominent numbers on the front of the fertilizer package. What  does  13-25-12 mean?

The numbers correspond to the percentages of three different compounds: Nitrogen, Phosphorous and Potash (or Potassium). Each can contribute to plant health. Nitrogen, along with other nutrients, helps plant foliage grow strong. It is used in large amounts by plants. Ever notice your lawn has a growth spurt after fertilizing? That’s likely Nitrogen at work. High Nitrogen fertilizers  make for quick growth but weaker plants, which can more easily succumb to pests and diseases

Phosphorous helps plants develop strong roots and abundant flowers and is very beneficial to sandy soils, which are common in Colorado. Phosphorous does not leach out of our soil, so continual additions are not needed in the landscape.

Potash aides in overall plant health. Front Range soils have ample potash, so it is not advised to add more in our soils. It won’t help either your garden or your wallet.

So which is best?   There is no one-size-fits-all answer, but in general:

  • Lush, flowering garden pots benefit from weekly feeding of water-soluble fertilizer high in phosphorous.
  •  Houseplants can benefit from fertilizers with equal numbers of each nutrient.
  •  In the garden, it is best to get your soil tested. Information can be found at: http://www.soiltestinglab.colostate.edu/. This will greatly help you add the correct nutrients for your soil and growing needs.

A word of caution: More is not better. Always follow the application instructions and give the plant time to absorb the nourishment.

Lots more information on fertilizers and soil amendments can be found at:  http://www.ext.colostate.edu/mg/gardennotes/234.pdf