Container and small space Gardening
"The tiniest garden is often the loveliest."
- Vita Sackville West
- Vita Sackville West
Introduction
in many situations, it is desirable to grow plants in containers or pots, such as on patios, in entryways, as house plants, and when there is not enough space or land to grow crop plants in the ground. Growing a plant in a container is very different from growing the same plant in ground. This is mostly due to the fact that the root system is restricted, and the physics of the container also restricts drainage from the pot. The atmosphere surrounding the pot does not have the same wicking properties as the soil below and around the roots growing in a field. The resulting situation is that a given soil in a pot holds more water than that same soil in a field. Common field soil containing silt and clay does not make for good potting media because it does not allow enough aeration for root systems. Despite these issues, container gardening is still a very popular method of cultivating both ornamental and crop plants, especially when living in a place where a balcony garden is your only option.
Creating a container garden space
Although when we think of a garden, we tend to envision a large, lush expanse of open land filled with flora and fauna, smaller container gardens can also bring unparalleled beauty to our spaces. Use of container gardening methods allows those without formal gardens to bring cultivated crops, flowers, and greenery to otherwise cold outdoor concrete areas. In the section below, you'll learn all about the basics and best practices of container gardening, and be able to create your own..
Assessing the Space
As is usually the first step in any project, the existing space needs to be assessed. Measuring a garden space will allow you to recognize the physical boundaries that your garden will have. It is important to note any existing appliances, gathering areas, or storage spaces that will cut into (and possibly need to be covered up by) container plants. Also note the type of surface you'll be placing your containers on. If it is a concrete surface, see if you can investigate how warm it gets when in direct sun for a number of hours. A big problem with growing plants in containers is that they overheat easily, which can kill fragile new roots and leach moisture from the container. If it is a wood decking surface, investigate how wide the spaces are between slats, and ensure that the structure can hold the weight of a patio garden (including containers, which can be heavy, and added water).
As is usually the first step in any project, the existing space needs to be assessed. Measuring a garden space will allow you to recognize the physical boundaries that your garden will have. It is important to note any existing appliances, gathering areas, or storage spaces that will cut into (and possibly need to be covered up by) container plants. Also note the type of surface you'll be placing your containers on. If it is a concrete surface, see if you can investigate how warm it gets when in direct sun for a number of hours. A big problem with growing plants in containers is that they overheat easily, which can kill fragile new roots and leach moisture from the container. If it is a wood decking surface, investigate how wide the spaces are between slats, and ensure that the structure can hold the weight of a patio garden (including containers, which can be heavy, and added water).
Container Selection
There are many different sizes, shapes, materials, and colors to choose from when selecting containers for your potted plants. Any container will do, as long as it has drainage holes. If you are using recycled containers, be sure to fully clean and sanitize them before using. Even if they look and feel clean, there could be residual pest eggs, diseases, or fungi hiding in nooks and crannies. A good solution to use for cleaning pots is a 9-part water to 1-part bleach; if containers are porous, make sure to soak the pot in cleaning solution so that all pores are sanitized.
Smaller containers and unglazed clay pots dry out the quickest in summertime. The smallest pot for outdoor use is about 8-12 inches in diameter and depth, although in partial shade, containers can be smaller. Deeper containers are better than wider containers, because they provide more space for root systems to grow in search of moisture and cooler temperatures lower down. Deeper containers allow plants to thrive, even in warm, summertime conditions when more frequent irrigation is usually required. As a general rule, containers should be about four inches deeper than the length of the roots when the plant has reached maturity.
Container colors and matierals?
There are many different sizes, shapes, materials, and colors to choose from when selecting containers for your potted plants. Any container will do, as long as it has drainage holes. If you are using recycled containers, be sure to fully clean and sanitize them before using. Even if they look and feel clean, there could be residual pest eggs, diseases, or fungi hiding in nooks and crannies. A good solution to use for cleaning pots is a 9-part water to 1-part bleach; if containers are porous, make sure to soak the pot in cleaning solution so that all pores are sanitized.
Smaller containers and unglazed clay pots dry out the quickest in summertime. The smallest pot for outdoor use is about 8-12 inches in diameter and depth, although in partial shade, containers can be smaller. Deeper containers are better than wider containers, because they provide more space for root systems to grow in search of moisture and cooler temperatures lower down. Deeper containers allow plants to thrive, even in warm, summertime conditions when more frequent irrigation is usually required. As a general rule, containers should be about four inches deeper than the length of the roots when the plant has reached maturity.
Container colors and matierals?
Soil
A good potting media must be well-drained for good aeration, but able to hold water and nutrients for the plant's use. Contrary to popular belief, placing gravel or stones at the bottom of a pot does not increase drainage. It simply reduces the water-holding capacity of the pot and raises the saturated zone in the pot, creating less room for roots. Potting soil is meant to support the plant in the pot and resist decomposition so that frequent repotting is not necessary. Various potting soil mixes are available for purchase, but home gardeners can also create their own.
The ideal potting soil mix is light, able to get we thoroughly and drain quickly. It should be able to hold about 40% of water by volume, retain around 10% air, and be free of weeds, diseases, and pest organisms. Creating a home-mix potting soil is a great way to ensure that your potted plants are getting everything they need in a soil. Potting soil should have 50% organic volume, and 50% inorganic volume. Any combination of the following ingredients can be used to comprise the inorganic half of the soil:
A good potting media must be well-drained for good aeration, but able to hold water and nutrients for the plant's use. Contrary to popular belief, placing gravel or stones at the bottom of a pot does not increase drainage. It simply reduces the water-holding capacity of the pot and raises the saturated zone in the pot, creating less room for roots. Potting soil is meant to support the plant in the pot and resist decomposition so that frequent repotting is not necessary. Various potting soil mixes are available for purchase, but home gardeners can also create their own.
The ideal potting soil mix is light, able to get we thoroughly and drain quickly. It should be able to hold about 40% of water by volume, retain around 10% air, and be free of weeds, diseases, and pest organisms. Creating a home-mix potting soil is a great way to ensure that your potted plants are getting everything they need in a soil. Potting soil should have 50% organic volume, and 50% inorganic volume. Any combination of the following ingredients can be used to comprise the inorganic half of the soil:
Perlite
Mined from lava flows and heated to form small, spongelike kernels. A very light, sterile addition that holds 3-4 times its weight in water. |
Builder's Sand (.25 to 1 mm diameter)
A heavy ingredient chock full of micro- nutrients due to its clay particle content. |
Vermiculite
Also known as 'expanded mica', this ingredient is a hydrated magnesium aluminum iron silicate. Lightweight, acid neutral, and absorbs water like a pro. |
Materials used to create the organic volume of potting soil include:
Once you have gathered your organic and inorganic materials, mix the inorganic and organic materials separately, and then add the inorganic and organic mixes together for a final blend. Fertilizer, if needed, is added last to the blend. To mix, it is ideal to use a large, hard, flat surface, like an outdoor patio or garage floor. Once you have prepared your mix, it can be used in containers or stored for several years. Container mixes can last as long as there are plants growing in it, though it is best to completely replace all potting soil every two to three years to ensure that good pore space is maintained for healthy root growth. A good practice is to pot up container plants every time the soil needs to be changed. Every year, as the soil breaks down, the level of soil in the container will lower; simply add more potting soil to the top of the container when this occurs.
Fertilizing Potted Plants
Fertilizer should be added to your potted soil mix as a last step, and can also be added to already potted soil, as well, to support the yearly growth of container-grown plants. A commercial, slow-release fertilizer is best; for example, a 16-16-16 coated fertilizer provides superior growth support for potted plants. Fertilizer added to the initial mix is considered a 'starter' feed, and will need to be replenished and supplemented with a topical application once plants are established. Plants in pots cannot search for more fertile soil using their root systems, as they are mechanically confined. They are essentially trapped, and require light, frequent feedings. About two to four weeks after planting, especially for vegetable crops, begin applying a water-soluble fertilizer mixed at a quarter strength at each watering. Great organic fertilizers include liquid fish emulsion, liquid kelp, and blood or bone meal. Whichever fertilizer is used, the most important task is to not overfertilize. The leaching of overfertilized soil is not as active in potted environments, because there is really nowhere else for the fertilizer to go. Overfertiized plants can exhibit a number of growth and development issues.
Fertilizer should be added to your potted soil mix as a last step, and can also be added to already potted soil, as well, to support the yearly growth of container-grown plants. A commercial, slow-release fertilizer is best; for example, a 16-16-16 coated fertilizer provides superior growth support for potted plants. Fertilizer added to the initial mix is considered a 'starter' feed, and will need to be replenished and supplemented with a topical application once plants are established. Plants in pots cannot search for more fertile soil using their root systems, as they are mechanically confined. They are essentially trapped, and require light, frequent feedings. About two to four weeks after planting, especially for vegetable crops, begin applying a water-soluble fertilizer mixed at a quarter strength at each watering. Great organic fertilizers include liquid fish emulsion, liquid kelp, and blood or bone meal. Whichever fertilizer is used, the most important task is to not overfertilize. The leaching of overfertilized soil is not as active in potted environments, because there is really nowhere else for the fertilizer to go. Overfertiized plants can exhibit a number of growth and development issues.
Watering Container Plants
As mentioned above, soil in containers will lose water more quickly than soil in the garden. There are techniques and cultural practices that can enhance the water retention of containers, but they will all dry out relatively quickly. Water requirements will vary, depending on the season; containers should be checked daily to ensure that adequate water is being provided. A good manual test for soil moisture is to stick a finger in the soil. If it feels damp in the top inch, there is no immediate need for water. If it feels dry, water the container until some leaks out the bottom. In the middle of summer when days are hot and long, and on windy days, watering may be needed on a daily basis. Using trays under pots can ensure that extra water is available to be reabsorbed by the soil in the pot. In wintertime, make sure to remove trays under containers so that roots do not rot under saturated soil conditions. As in any garden, watering is best done in the early mornings and in small doses to avoid wasting water and to ensure that leaves do not stay wet all night. A layer of mulch in containers will assist with soil moisture retention, especially in the summertime.
Dealing with Hydrophobic Soil
Someteims, soil can dry out and become water-repellent. This is called Hydrophobic soil, and it's essentially soil that resists absorbing water. This causes water to bead up on the surface and run off, instead of moving downward through the topsoil and the rest of the soil profile. There is often an easy fix. Soil must be rehydrated so that it can retain moisture properly going forward. Water soil slowly and deeply to encourage water penetration and discourage runoff. Water thoroughly, and then return 15 minutes later and water again, then repeat once more. This should hydrate the soil enough so that it retains water for longer and you can continue a normal watering schedule going forward. In addition, you can improve the following about soil to bring it back to its former glory:
- Aeration: Improve by tilling or aerating soil. This will break up hydrophobic soil layers and promote water infiltration.
- Organic Matter: Incorporate organic matter into the soil (like compost or mulch). Organic material can improve soil structure as well as improve water retention.
- Mulching: Apply a layer of mulch on the soil surface to reduce evaporation and prevent soil from drying out.
As mentioned above, soil in containers will lose water more quickly than soil in the garden. There are techniques and cultural practices that can enhance the water retention of containers, but they will all dry out relatively quickly. Water requirements will vary, depending on the season; containers should be checked daily to ensure that adequate water is being provided. A good manual test for soil moisture is to stick a finger in the soil. If it feels damp in the top inch, there is no immediate need for water. If it feels dry, water the container until some leaks out the bottom. In the middle of summer when days are hot and long, and on windy days, watering may be needed on a daily basis. Using trays under pots can ensure that extra water is available to be reabsorbed by the soil in the pot. In wintertime, make sure to remove trays under containers so that roots do not rot under saturated soil conditions. As in any garden, watering is best done in the early mornings and in small doses to avoid wasting water and to ensure that leaves do not stay wet all night. A layer of mulch in containers will assist with soil moisture retention, especially in the summertime.
Dealing with Hydrophobic Soil
Someteims, soil can dry out and become water-repellent. This is called Hydrophobic soil, and it's essentially soil that resists absorbing water. This causes water to bead up on the surface and run off, instead of moving downward through the topsoil and the rest of the soil profile. There is often an easy fix. Soil must be rehydrated so that it can retain moisture properly going forward. Water soil slowly and deeply to encourage water penetration and discourage runoff. Water thoroughly, and then return 15 minutes later and water again, then repeat once more. This should hydrate the soil enough so that it retains water for longer and you can continue a normal watering schedule going forward. In addition, you can improve the following about soil to bring it back to its former glory:
- Aeration: Improve by tilling or aerating soil. This will break up hydrophobic soil layers and promote water infiltration.
- Organic Matter: Incorporate organic matter into the soil (like compost or mulch). Organic material can improve soil structure as well as improve water retention.
- Mulching: Apply a layer of mulch on the soil surface to reduce evaporation and prevent soil from drying out.
Designing with Potted Plants
Thriller, filler, spiller method
How to arrange pots on a patio
hiding eyesores
Thriller, filler, spiller method
How to arrange pots on a patio
hiding eyesores
Ornamental Plants that do well in containers
Growing vegetables in containers
In urban areas, many residents believe that they simply do not have the space or infrastructure set up to support growing vegetables in their small spaces. However, many vegetable crops can be grown in pots, and they can actually put out a good harvest year after year if cared for correctly. There are a few major considerations to work through when designing and preparing for a vegetable container garden, outlined below. |
Assess Sun Patterns
In areas where container gardening is necessary, sun can be a limiting factor to where and what is planted. Plants need to be chosen according to the amount of sun or shade they'll get each day, and many vegetables need around 6-8 hours of direct sun each day. Leafy vegetables (like lettuce, onions, carrots, and beets) will perform alright in partial shade, but plants that bear fruit will need more than 8 hours of full sun conditions.
In areas where container gardening is necessary, sun can be a limiting factor to where and what is planted. Plants need to be chosen according to the amount of sun or shade they'll get each day, and many vegetables need around 6-8 hours of direct sun each day. Leafy vegetables (like lettuce, onions, carrots, and beets) will perform alright in partial shade, but plants that bear fruit will need more than 8 hours of full sun conditions.
Choose Plants
Certain groups of plants have needs that will dictate if they can be grown in certain conditions. For example, herbs, lettuce, green onions, radishes and spinach are great for beginners, because they are shallow-rooted and simple to grow. Crops like potatoes, carrots, turnips, and other root vegetables need to be planted in much deeper containers to allow them enough space for production. There are also tall vegetables and sprawling crops, like eggplant, peppers, squash, and tomatoes) that will require more space for their extensive root systems. These crops will do well, as long as they have enough root space.
To make the most out of limited space, choose plants that are dwarf varieties; these have been bred to do well in small spaces and will still produce well, though their fruit is usually smaller than full-size varieties. Dwarf crops that do well in containers include beans, beets, lettuce, peppers, radishes, and some varieties of summer squash and tomatoes. Choose short and bushy over large and sprawling or vining. For the highest yield, provide trailing or vining crops with structure to climb (like stakes or trellises) during the initial planting. Waiting to add structures can damage new roots when installed later.
Although it may seem a bit counterintuitive, choose plants that are smaller (less developed). This will allow their root systems to be able to form in their 'forever pot', rather than having to make large adjustments and rewire themselves after spending more of their lives in a nursery pot. A good size to purchase are 4-inchers or plants that come in 6-packs. Gallon size plants are way too big, and transplanting them can cause enough shock that they do not produce fruit in the same season. The chart below will provide you with a general idea of which plants will do well in your container garden, organized by mature root depth (shallow, moderate, and deep).
Certain groups of plants have needs that will dictate if they can be grown in certain conditions. For example, herbs, lettuce, green onions, radishes and spinach are great for beginners, because they are shallow-rooted and simple to grow. Crops like potatoes, carrots, turnips, and other root vegetables need to be planted in much deeper containers to allow them enough space for production. There are also tall vegetables and sprawling crops, like eggplant, peppers, squash, and tomatoes) that will require more space for their extensive root systems. These crops will do well, as long as they have enough root space.
To make the most out of limited space, choose plants that are dwarf varieties; these have been bred to do well in small spaces and will still produce well, though their fruit is usually smaller than full-size varieties. Dwarf crops that do well in containers include beans, beets, lettuce, peppers, radishes, and some varieties of summer squash and tomatoes. Choose short and bushy over large and sprawling or vining. For the highest yield, provide trailing or vining crops with structure to climb (like stakes or trellises) during the initial planting. Waiting to add structures can damage new roots when installed later.
Although it may seem a bit counterintuitive, choose plants that are smaller (less developed). This will allow their root systems to be able to form in their 'forever pot', rather than having to make large adjustments and rewire themselves after spending more of their lives in a nursery pot. A good size to purchase are 4-inchers or plants that come in 6-packs. Gallon size plants are way too big, and transplanting them can cause enough shock that they do not produce fruit in the same season. The chart below will provide you with a general idea of which plants will do well in your container garden, organized by mature root depth (shallow, moderate, and deep).
Plant
Beets
Leaf Lettuce Onions Radishes Spinach Swiss Chard |
Spacing
3" apart
6" apart 3" apart 1-2" apart 5" apart 6" apart |
Soil Depth
9" to 12"
9" to 12" 9" to 12" 9" to 12" 9" to 12" 9" to 12" |
Broccoli
Cabbage Caulifrlower Cherry Tomatoes Eggplant Peas Peppers Carrots |
12" apart
12" apart 12" apart 12" apart 12" apart 3" apart 12" apart 2" apart |
12" to 14"
12" to 14" 12" to 14" 14" to 16" 14" to 16" 14" to 16" 14" to 16" 9" to 18" |
Beans
Cucumbers Potatoes Summer Squash |
8" apart
12" apart 6" apart 18" apart |
16" to 18"
16" to 18" 16" to 18" 16" to 18" |
To Sow or Not to Sow
There are some crops that will perform better if grown from seed, and others that do well as transplants. Beans, beets, carrots, cucumbers, lettuce, peas, radishes and squash do well when grown from seed. Plants like eggplant, peppers, and tomatoes are best when purchased as transplants. For more information on growing plants from seed, visit the seed module, linked below. |
Example Container Vegetable Gardens
A great example of a wood patio vegetable garden; although the containers are small, they can hold a lot.
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Crops like bush or vine-type cucumbers, peas, and cherry tomatoes can do well in hanging baskets, which frees up ground space for other plants.
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Squash grown in containers can do well if they're provided large enough pots for their extensive root systems.
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Galvanized steel tubs have increased space for root growth and copious square footage to allow for multiple plantings per container.
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Veggies can be mixed in with ornamentals for a both visually appealing and very useful small garden space.
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There are many different ways to provide growing medium for patio plants; if you can't bring the plants to the soil, bring the soil to the plants!
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