Categoría: jardinería en contenedores

Give a Thought to the Pot

En Por durhammastergardenersEn annuals, container gardening, Durham NC, gardening, gardening in pots, Gardening information, gardening NC, growing media, how to choose pots for container gardening, perched water table, potting soil, Uncategorized

By Deborah Pilkington, NC State Extension Master GardenerSM volunteer of Durham County

Container gardeners, me included, give a lot of thought to choosing which plants will go into the containers.  But not a lot of thought is given to the containers themselves.  Yet, to have a successful container garden in full sun, shade, or anywhere in between, the choice of pot is as important as the choice of plant.  So, for the next few minutes, we’re going to look at factors that should be considered for container choices, especially in our newly-designated hardiness zone 8. 

Porosity

Examples of porous pots. (Image credit: Deborah Pilkington)

Some containers, such as the familiar terra cotta (“baked earth” in Italian) are very porous, meaning the pot draws water from the potting media through its walls. Other porous materials include hypertufa, unglazed ceramic, and clay. Because of this, these porous pots may require more frequent watering, something to think about if they are going to be in full sun. Less porous choices would be wood or concrete, and the least porous pots are made of metal, fiberglass, plastic, or glazed ceramic.  That means they are going to help the potting mix conserve water.  

Size

The smaller the pot size, the more frequently it will need to be watered, sometimes more than once a day. A larger container is going to be heavier and less likely to tip over. Larger containers will require less frequent watering but can be a bear to move from location to location…unless you own one of these (see the photo below). And the cost of filling the container with potting mix is also a consideration.

The difficulty of moving very large pots! (Image credit: Deborah Pilkington)

Fragility

If a container is fragile and susceptible to cracking in cold temperatures, it will need to be moved to a sheltered area for winter.  Terra cotta, clay, unglazed ceramic, and hypertufa are all fragile materials. The sturdiest are metal, plastic, concrete and wood.

Heat Holders

Metal containers, and dark-colored containers are heat holders in full sun. They can even be hot to the touch! Potting mix in these containers can rise to well over 100°F. Keeping roots well-watered, unless you are growing cactus, is a must. 

Shape

If you are going to grow a shrub or tree in a container, at some point the plant will need to be lifted from the container to be root pruned—an onerous but necessary task.  So, for shrubs or trees you want to choose a container that is wider at the top (below on the right) rather than narrower (below on the left) to make lifting easier. 

(Left) This container is more narrow at the top and would make it difficult to remove a shrub that had grown in the pot. (Right) In contrast, this pot is wider at the top than the bottom and it would be easier to remove a shrub that had been grown in the pot. (Image credit: Deborah Pilkington)

Drainage

Good drainage is a must in container gardening.  If the container doesn’t have drainage holes, you can add them using a drill and the appropriate drill bit. And to ensure correct drainage, don’t put anything in the bottom of your container but soil mix. Adding gravel or covering the hole with broken terra cotta not only defeats the purpose of ensuring drainage, but it also raises the level of the perched water table, moving the level of saturated soil even higher in the container and closer to the roots.

Drilling holes in metal containers at Cocoa Cinnamon Demo Garden on Geer Street. (Image credit: Deborah Pilkington)

For gardeners with limited space, especially the newcomers to Durham’s condominiums and apartments with balconies, container gardening can bring some beauty and food to your home.  For urban container gardening inspiration, visit the International Award-Winning Master GardenerSM Container Demonstration Garden at Cocoa Cinnamon at Foster and Geer streets in Durham.

Get more ideas on container gardening by visiting the Cocoa Cinnamon Demonstration Garden at 420 West Geer Street in Durham, NC. (Image credit: Deborah Pilkington)

Recursos e información adicional

Check out the links below to learn more about plant hardiness zones including the history and factors used to determine the hardiness zone of an area. What does this really mean for North Carolina gardeners?

2023 USDA Plant Hardiness Zone Map | USDA Plant Hardiness Zone Map

Gardening Association of North Carolina – 2023 USDA Plant Zone Update (gaonc.org)

AN ILLUSTRATED HISTORY OF AMERICA’S PLANT HARDINESS ZONES (With a Closing Look at North Carolina) | by Tom Packer

For more information on perched water tables and soilless media check out the below online guide about drainage for containers.

How to Improve Drainage in Plant Pots, The Proper Way to Do It! – Deep Green Permaculture

If you want to take a deep dive into the physics of water movement in soilless media and media components, visit the following links.

Growing Media (Potting Soil) for Containers | University of Maryland Extension (umd.edu)

Homemade Potting Media (psu.edu) — How to make your own potting media

Learn more about choosing pots with the in-depth article below.

Containers, Pots, and Planters: What Material Is Best? (gardenerspath.com)–

Enlace breve del artículo: https://wp.me/p2nIr1-4sZ

How to Make a Hypertufa Planter

En Por durhammastergardenersEn container gardening, Uncategorized

By Marcia Kirinus, NC State Extension Master GardenerSM volunteer

The doldrums of winter are now upon us, but there’s still plenty of work to be done to prepare your garden (either indoor or outdoor) for the more productive seasons ahead. For example, did you know with a bit of planning and some common materials, you can create your own plant containers from scratch? Known as hypertufa containers, these vessels can be a fun craft and a welcome addition to your container collection.

What is Hypertufa?

It is a lightweight, manmade, frost-resistant material that is molded to make outdoor planting vessels, garden art, and even outdoor pizza ovens given its high heat tolerance. Hypertufa ingredients are typically portland cement, peat moss, perlite, and water. However, you can substitute peat moss for a more renewable resource like coco fiber. You may also choose to use vermiculite instead of perlite –  note that perlite seems to add strength where vermiculite makes your mix more pliable.

Various hypertufa pots. (Left to right) Alpine plants in hypertufa at Oliver Nursery, Fairfield, Connecticut; hypertufa collection at Sarah P. Duke Gardens; evergreens in hypertufa at NCSU’s JC Raulston Arboretum. Image credits: Marcia Kirinus

Etymology of Hypertufa

Say it out loud – “HY-PER-TOOF-A.” Such a funny word. “Tufa” is a natural volcanic composite known worldwide.  In southern Italy entire towns are built out of tufa. Elegant homes, roads, and walls that date back to the Neolithic Age, all were built completely from tufa. “Hyper” would refer to, ’over the top’, so the word literally means, ‘over-the-top tufa.’

Civita di Bagnoregio, Italy, is an ancient Etruscan town hewn atop a hill of tufa. Image credit: Pixabay

What can I make from Hypertufa? 

A typical application for hypertufa is to make planting troughs that resemble old stone troughs from Europe, which can be an elegant and timeless addition to any outdoor garden. However, unlike heavy stone troughs or vessels, hypertufa is incredibly light, and you get to customize it and alter variables such as size, shape, depth, texture, and even color. Small spring bulbs do great in these types of vessels, planted over with lettuce, kale or arugula.

Natural stone trough used to water livestock. Image from Negarden.

Materials List:

Mold

  • Insulation board for mold – 4 sides and a bottom. Remember your pot will be built inside this mold so the final piece will be smaller than your mold.
  • Roofing nails, 1 1/2”
  • Blue painter’s or masking tape

Recipe

  • 1 part Portland cement
  • 2 parts peat moss
  • 1 part perlite or vermiculite
  • Handful of poly fibers (can buy this online)

Tools

  • A bucket that you will use as a measuring vessel. I normally use a 5 gallon bucket , but the size you use will depend on the size of your final product. 
  • Sieve to sift peat moss.  You don’t want large chunks or twigs. Hardware cloth works well. 
  • Dust mask
  • Waterproof or nitrile gloves
  • Plastic sheet that you can use to cover your hypertufa for 30 days. A trash bag is fine.
  • Wire brush or other shaping tools used to remove rough corners and texturize your final piece. This is done soon after you unfold. 
  • Hose with shut off and watering wand
  • Clothes that you can get dirty
  • Wheelbarrow for mixing. If you don’t have a wheelbarrow, you could mix it in a large plastic tub.
A simple bowl form and a trough using 1″-thick styrofoam, roofing nails, blue tape. Note plastic shot glasses used as feet for the trough. Image credit: Marcia Kirinus

The Setup:

  • Do this outside or in a space you don’t mind getting dirty like a garage. You can put a drop cloth down if needed. This is a messy process.
  • Don’t start this project at the end of the day. Set up will take a bit of time and you don’t want to rush. You should use the entire batch of hypertufa once you add water.
  • You need a level working surface of comfortable working height
Making hypertufa troughs at Durham Flower Farm. Note set up and finished troughs in the background. Image credit: Marcia Kirinus

Making a Hypertufa Vessel:

Step one

  • Choose a mold. A mold can be anything that is flexible or that breaks away. In the past I’ve used lamp shades, sink bowls, and plastic containers of various sizes and shapes. 
  • If you want to make a trough, the easiest mold is one you make out of  1″ thick insulation board.  You can find this in the drywall/insulation section of your home improvement store. The styrofoam is easy to cut with a utility knife and it breaks away from your trough without trouble. 
  • To hold the four walls together you will use nails and masking or blue tape.  Roofing nails work best as they have a big head and pointed narrow body that you can easily insert into the board.  You will first insert the nails, then wrap it tightly with masking/blue tape.

(Left to right) Sink vessel used as a mold. Resulting hypertufa planted with wood hyacinth, (Hyacinthoides hispanica). Old lampshade used as a mold, resulting hypertufa planted with night blooming Cereus, (Cereus sp.) Image credit: Marcia Kirinus

Step two

  • Glove up (I double glove) and don a mask. Don’t breath in any dust – cement, perlite, vermiculite or peat which can be harmful to your lungs. 
  • Run peat moss though a sieve to remove large pieces and twigs.  1/4″ hardware cloth works well.
  • Mix all ingredients well until you do not see individual components of mix. The color should be uniform.
  • Add a small handful of poly fiber. This is used to add strength to a pot. 
  • Add water until consistency is firm and workable. Make sure mix is uniform. Keep material covered with plastic and use in small amounts.

Step three

  • Start building your vessel from the bottom up. Pack the material in the mold, firmly pushing down to ensure there are no air pockets. Use the “pattycake” method, which is like making a hamburger (or a mud pie from your childhood). Build your floor first. Keep the bottom and walls uniform and about 1” thick. The part that is most visible is the rim of your vessel so do a fantastic job with that. 
  • Don’t forget to make two to three holes at the bottom of your pot for drainage. I use a pencil for this. 
Bottom of hypertufa is made, now building up the sides starting in the corners.
Image credit: Marcia Kirinus
Finishing up the rim of trough. Image credit: Marcia Kirinus

24 hours later

  • Remove tape and nails from your mold. 
  • Gently begin popping off the sides. The idea is to introduce air between the mold and hypertufa. Never pry the mold off. Once sides are off, assess if it is dry enough to slide the hypertufa on its base – introducing air to the bottom of the hypertufa so it does not cement itself to the base. You will know if it is dry enough if chunks or pieces do not fall off your tufa when you manipulate it. 
  • Once the vessel is free of the mold, clean up the rim, scrape off extra pieces and sharp edges with a wire brush  or other tool. This can be done with anything like a butter knife, paint scraper, popsicle stick…. You can also use tools at this point to create a pattern on the surface of your tufa. Just be gentle. 
  • Cover with plastic and don’t look at it again for 30 days. The best place to cure it is in a shed or garage. Avoid putting it on the ground or in a sunny hot spot. Wherever you put it, keep a plastic cover over it so it dries slowly. Rain is okay.

30 days later

  • In 30 days your hypertufa is ready to be planted. It is rock solid but it will continue to cure and change color over time.

Planted trough with succulents becomes a complete garden. Image credit: Cornell Cooperative Extension of Erie County.

Additional Tips: 

  • Never use only one hand to lift your pot.  It is very fragile until it cures. Always support all sides of your hypertufa and keep it flat. Do not bump it or move hastily with it. You might need help lifting. 
  • When you are making your vessel, have extra molds on hand if you have left over material. You need to use up all of your material or waste it. 
  • Anything can be a mold. Besides lamp shades and old sink vessels, I have used plastic shot glasses, small yogurt containers, and paper dixie cups to act as feet for my troughs. Be creative. 
  • Thrift and discount stores have a variety of “molds.” I also purchased a wire trash can to use as a sieve. It was perfect. 

Additional Reading:

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