Seven Container Gardening Basics Every Gardener Should Know

Here are the things you need to know — container gardening basics — to succeed in your own garden.

One of the delights of our summer garden is our container gardening. We use them in a variety of ways and whether you have acres of gardens or a postage stamp patio, you might consider the use of containers to extend and improve the range of plants you grow.

Salvia argentea (biennial) in a container with annuals and sweet peas

What Plants Can I Grow In Containers?

To begin with, any plant you can name can be grown in a container.
 I know that some garden books will say give just the contrary advice but if I can grow plants -from bananas to cosmos and roses to zinnias in a container, I don’t see why you can’t. I used to grow my lavender collection in containers beside our front door and they lend a certain “style” and fragrance to our entrance way.

Potted tulips Image by author

What Soil To Use

Good container soil is the key to success. Use a good quality soilless mix  in the container. Don’t use a cheap brand or regular garden soil because they will compact and turn to concrete over the course of the summer. A good soilless mix is composed mostly of peat moss and perlite (perhaps with a very small amount of compost) and that’s about all.

A good soil like Pro-mix or Fafard will more than pay for themselves in superior plant performance this summer. And, they are light enough that you can still move most containers even when fully filled.

How To Feed

I also use a fish emulsion fertilizer on a weekly basis for my container plants. This stuff is the best container food in the world, producing huge, fragrant rose blossoms and jungle-like growth on our window boxes. There’s nothing else like it because it has all the major and minor nutrients a container plant needs.

Most other liquid fertilizers lack the minor and trace elements a plant requires for superior growth. Remember that soilless mixes, unlike natural mineral soils in your garden, do not have these trace elements as part of their natural composition so you have to provide them if you want your plants to grow properly.

The Essential Watering Rule

There’s a very simple rule of thumb for growing vegetables in a container or anything else for that matter: Water until water pours out the bottom.

In this way, you know all the soil, from top to bottom is thoroughly wet.

Air Temperatures To Understand

Somewhere around 83F (a bit higher for some and lower for others) plant leaves stop respiration and shut down to conserve water. They essentially stop growing. Because a plant actually gets taller, grows leaves etc at night after the day’s energy has been stored, this high day temperature will reduce the ability of the plant to grow.

In extremely high heat periods, it’s a good idea to give container plants a part shade condition — even those that grow in the sun. Simply pick up and move your containers during the heat of the day or tuck them into a part sun spot until the heat wave is over.

Not much you can do about this but you can control the next variable.

Image courtesy Pixabay

The above picture isn’t my kind of container garden but I’ve seen these (and other interesting containers on my travels)

Soil Temperatures in Containers

Soil temperatures will also stop growth through reduced nutrient uptake — the higher the soil temperature, the less food the plant absorbs.

Soil gets hotter in smaller containers — it easily approaches air temperature in small containers. Dark colored containers — such as black plastic — absorb more heat and get hotter.

Adding water to “cool down” the plant will only swamp the plant and kill it.
 The solution is to use light, reflective colored containers and to give plants some shade during the heat of the day.

Where Can I Grow Containers

The bonus of container growing plants is that you can place the container where you need it. For example, if you have a paved patio but want to grow plants up a trellis, then simply put a large container beside the trellis and plant morning glory seeds in the container. Those seeds will germinate quickly and if you train them towards the trellis (gently lay them down in the direction of the trellis when they threaten to go the other way) they’ll quickly find it and start climbing.

You could use the back of a round container for morning glory seeds and fill the front with impatiens and trailing lobelia so your container not only grows upwards but also gives you a flower show.

Multi-layer Your Planting

That’s another key to remember. Don’t just think of your containers as having just one use. We used to grow pansies under our containerized roses. The pansies would give us a great show in the early spring before the rose had leaved out and then would climb upwards into the rose when the rose shaded it. The pansy would act like a short vine and would poke its flowers out in unexpected spots. As I recall, we used a mid-blue pansy with a peach coloured rose to give a super colour combination.

You can also tuck herbs like basil into flower pots so you can harvest a few leaves whenever the need for a toasted tomato sandwich strikes (you *have* to use basil on those sandwiches if you want to really experience the joy of a tomato sandwich) I note that if a container is large enough for 8 full, large shovels full of soil, it is large enough (with daily or twice-daily watering) to grow a tomato plant.

Water Plants — Why Not?

Why not plug up the hole of a container and grow small water lilies in one. I did this last year and the lily was a great hit in the garden. I even managed to keep a few small rosy barb fish alive all summer in one clay-coloured container that was semi-shaded.

I did however discover the hard way that the high water temperatures generated in small black plastic above-ground water containers were not good for fish even if it was great for the dwarf lilies.

Image courtesy at Pixabay

Perennials and Winter Survival

One of the newest gardening trends is to grow perennials in garden containers and I confess I’ve done this for many years now. The only problem with this is with winter survival. In the case of our lavenders, they spend the winter on our porch. The porch is protected from the wind and moderated by house temperatures and the lavenders survive nicely.

Your attached garage would be equally appropriate. A garage or shed that is not protected by house heat would be too cold for good winter survival. (We don’t want perennial roots to get to 5F.)

An alternative suggested by some writers is to dig the perennials out of the pot and plant them in the garden for the winter. You can then dig them up for the container in the spring or simply leave them in the garden to grow. There is no perennial that will not survive in a large container so you are only limited by your imagination.

And that’s the essence of good container gardening. Get a big enough container (I use 16 inch clay pots) and a big enough imagination and you can extend your gardening and growing to anywhere you happen to spend some time.

I’ve answered more than these questions in my Container Gardening ebook here on Amazon. 

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A Perennial Plant List for Hummingbird Gardens

Please understand that this is not an exhaustive list of plants for hummingbird gardens but just the most common plants.

What Do Hummingbirds Really Eat?

Hummingbirds get the majority of their food from insects such as aphids so putting up plants like honeysuckle that attract aphids will attract the birds for both the flower shape and the insect food the plant sustains.

We used to get hummingbirds into our greenhouses every spring.

They would arrive in the north and a flowering greenhouse was too good an opportunity for them. They would buzz in and out tremendously amusing us all.

You could always tell the rookies. They would get inside and not know how to go back out the doors or vents. They would try to fly up and out through the plastic, an effort that thankfully never worked.

After several minutes of buzzing and beating themselves up against the plastic, they would perch on a cross wire or hanging basket and survey the place. More than once, they’d land on a shoulder or a hand.

Sooner or later they would see a door or somebody going out the door and they’d figure it out. Zooom and away they’d go.

The experienced birds used the vents- in and out without at any time of day

If you have a humminbird feeder – do not add red dye to the sugar-water mix. The birds don’t need it to find the feeder and it does them no good.

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In any case, use these plants as backbone plants for your hummingbird gardens:

Perennial Plant List:

  • Agastache
  • Alcea
  • Aquilegia
  • Buddleia
  • Dahlia
  • Delphinium
  • Digitalis
  • Heuchera
  • Kniphofia
  • Lilium
  • Lobelia
  • Lonicera
  • Lupinus
  • Mimulus
  • Monarda
  • Penstemon
  • Phlox
  • Phygelius
  • Salvia
  • Sidalcea
  • Leonotis
  • Leycesteria
  • Meehania
  • Spigelia
  • Weigela
  • Zauschneria

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Why Perennials May Not Grow Quickly When You First Plant Them

Ever wonder why you buy perennials in the spring and they just sit there for a month or two before they start growing? Most of the time, we blame it on “culture shock” or “transplanting” or any number of other cultural things.

Plant Growth Regulators

Many nurseries use a plant growth regulators (PGR) to slow growth down so the plants don’t leap out of the pots.

And trust me, this was a problem in our nursery as the plants would leap out and start growing at the hint of spring. We had all kinds of spacing activities to keep them all growing, yet bushy and looking good for retail sales. (We didn’t use PGR’s)

But the kicker in this is most common growth regulators last 8-12 weeks and in the spring, instead of growing like crazy, the plant grows bushy and shorter. Again, it makes a better selling plant.

But that chemical still persists and is acting when you take the plant home. It stays short and bushy and really doesn’t get growing “normally”. Or as normally as it would if you did it at home.

Have you seen my perennial ebooks?

You get a bushier plant. But one that’s slower to begin growing strongly.
That’s one effect of a Plant Growth Hormone Regulator (PGR)
And now you know why some of your new plants might not jump right into growing when you first plant them.

p.s. the effects of PGR typically disappear at 8-12 weeks so after that, growth should be normal. So figure 4-6 weeks in the nursery and 4-6 weeks at your garden. If it isn’t growing after 4-6 weeks in your garden, then you may have other issues.

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Why You Need Beneficial Bacteria In Your Pond

Before we can talk about beneficial bacteria in your pond, it is important to understand the basics of why you use them.

Bottom line – the water will be healthier faster if you add them. If you do not add them yourself, the beneficial bacteria will appear but it will take them anywhere from a month to eight weeks to become effective

If You Have Fish in Your Pond

And we really only worry about adding pond bacteria if we have fish in the water. If no fish, then in a practical sense, it is not vital to add beneficial bacteria. (useful but not vital to the plant health)

Nitrogen Cycle – The Simple Explanation (but useful to know)

We add beneficial bacteria to deal with the”Basic Nitrification Cycle”.
Now before you go and turn off your mind with this term, it really only means that fish excrete waste and this waste is ammonia and the water has to handle this poisonous material if it is to remain healthy.

Bacteria have been doing this in nature and we need to establish these beneficial bacteria in our pond. That’s the basics.

You can add it yourself or you can let Mother Nature take her time to do it. Adding it is faster but Mother Nature will do it for you

If you’re still with me, then let me take you a little deeper into this fascinating world. In a mature pond, the pond bacteria in the work on the water going across its media and turn the ammonia into a form of nitrogen (ammonia is another form of nitrogen) called nitrites. Then a second bacteria gets into the act and converts the nitrites into nitrates.

While the ammonia and nitrites are poisonous to fish and plants, nitrates are not.

All this happens in the biofilter and you can see why it is important to have this filter properly sized for the pond and the number of fish you intend to keep.

Why It is Important To Size Your Biofilter Properly

If the fish produce more waste (ammonia) than the biofilter can process, your pond will go out of balance and you’ll have water problems (dead fish included).

And just to make life even more interesting, the kind of fish you keep can determine the load on the filter.

For example, koi are huge feeders and eat approximately three times more than goldfish. This means that they excrete three times more than goldfish too. (roughly). If one koi excretes three times the ammonia as a goldfish, you can keep one koi or three goldfish of the same size for the size of the filter. In other words, you can keep three times more goldfish in the same pond than you could koi.

The Problem with Overfeeding Fish

If you overfeed your fish, you’ll also have higher levels of ammonia to deal with.
Remember that in a natural lake, the fish population is not as concentrated as in your pond, the population densities are much lower. And this gives the natural filters time to do their work; the beneficial bacteria congregate on all the minute cracks in rocks, between sand grains, etc to work on converting pond ammonia.

Beneficial bacteria also require oxygen to survive. This is why it is important to have a good water flow so that the oxygen can be absorbed by the water. This absorption takes place at the water surface and if the water is kept moving, more oxygen molecules can be put into contact with water molecules.

Role of the Biofilter in All This

The biofilter then is a critical component of our pond as it works to keep the bacteria alive and also as an effective interface between oxygen and the water surface. You’ll find an entire industry advocating that you use its filter material to produce this interface. As a rule of thumb, the more surface you can create for bacteria to live in your biofilter, the better.

And yes, you do have to run your filter 24/7 if you want your pond to stay healthy and alive. The minute you take the oxygen away from these nitrifying bacteria, is the minute the bacteria start to die and your pond starts to go bad. Small ponds (hard plastic preformed liners) can use filters that are installed in the pond. Bigger ponds will require a separate biofilter.

Remember that is easy to create a system where there isn’t enough oxygen in the water to handle the bio-load. It is impossible to put too much oxygen into the water so do design a beneficial bacteria system that will handle your projected fish and plant counts.

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The Bottom Line

Beneficial bacteria jump-start the workings of the bio-filter and are a way to get your pond clear faster in the spring. Mother Nature will do it but still – doing it yourself is faster to get rid of green water and get that filter working.

Sources for Products Mentioned on This Page

Multiple vendors of beneficial bacteria for ponds and different sizes for small to large ponds
Different sizes and models of biofilters for your small or large pond


How To Control Botrytis In Your Garden

This fungus is the major fungal problem in our gardening world. It is the grey mouldy stuff that appears on spent blossoms and attacks wounded leaves.

Think of it as Mother Nature’s shock troops – when there’s something that’s ready for composting, botrytis is sent in to start the job. When it’s done, other organisms take over.

This gives us the first clue about how it gets started.

The plants are under stress. This is normally being too crowded on the growing tables or garden.

High humidity is beloved of fungus everywhere and it’s no exception here.

Darkish conditions – either from shading or too much cloud cover outdoors is also a huge benefit to botrytis.

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So what you’re looking at here is cleanliness is next to godliness. (at least that’s what my mom used to tell me when she looked into my bedroom while shaking her head) – leaving any kind of infected material around is a sure way to get other plants infected.

  • Space out your seedlings, and garden plants to the correct distances.
  • With seedlings, keep at the right temperatures
  • In both the seedling trays and garden, make sure there’s adequate ventilation to keep those leaves dry.

Do those things right and your need for a spray will be eliminated.

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Three Real Uses For Coffee Grounds And Gardening

Coffee grounds and gardening might not seem like a match made in heaven as there’s some evidence to show that we should be using this very abundant waste product in our gardening efforts.

And most of us have lots of this product so here’s how to work both ends against the middle and use this product.

The first thing to be aware of is there’s a lot of misinformation and unproven data out there about coffee grounds in the garden.

The Research on Coffee Grounds & Slugs

The research on slugs and caffeine shows that concentrations of caffeine as low as .01 % reduces feeding by slugs (they avoid caffeine treated leaves) but that it doesn’t kill them at that rate.

A 1% solution can be expected to kill 60% of slugs while a 2% caffeine solution will knock out 95% of all slugs. This 2% solution is more effective than the chemical normally used in slug control. (metaldehyde)

The 2% solution also damaged some foliage on the tropical plants being used to feed the slugs. This calls into caution the use of caffeine on more tender leaved plants.

So where does this leave you with your morning coffee grounds – and your garden uses?

Fresh coffee contains approximately .05% caffeine. Which is a heck of a long way from the 1% solution you need.

This means that coffee grounds and fresh coffee will not kill slugs.

Coffee Grounds In The Garden Mulch?


Used coffee grounds make an excellent mulch. Note that they are acidic with a pH of between 3.0 and 5.0.

BUT when they finish decomposing, they will be neutral (finished compost tends to be neutral) So they do not turn the soil acidic.

They can be used thinly all over the regular garden as organic matter so you can simply toss your used coffee grounds onto the garden if you like. Unless you’re adding inches of this stuff (in truckload quantities) to the garden, you’re not going to see a difference in your soil pH.

If you do add a massive quantity in one spot, you may want to dig them into the garden as there are reports that they will develop a fungal layer if left exposed to the air.

Coffee Grounds and Worms

Coffee grounds are beloved by worms. I used to have a worm bin and you could almost hear the cheer when I toss in the morning’s makings of used coffee grounds.

So if you have a vermiculture setup, use the grounds as a food source. If not, simply toss them onto the garden and the worms will find them.

Toss them out daily into the garden or into the compost bin to avoid fly buildups.

Composting Coffee Grounds

And they should go into your regular compost bin because they compost very well in the compost bin. They have a carbon-to-nitrogen ratio of 20:1, roughly the same as grass clippings. After making the morning wakeup, coffee grounds contain up to 2% nitrogen. So for composting purposes, consider coffee grounds “green” material similar to grass clippings.

And one of the interesting things about composting coffee grounds is that the microbes that do the composting will turn the coffee from acidic to a neutral pH.

So coffee does not make compost acidic.

So that’s all the real news about coffee grounds and gardening.

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Doug’s Summary Notes

I hope this clears up some of the worst of the coffee ground garden rumours.

The one I hear the most is that the grounds will kill slugs or deter insects. If you get lucky, they “may” deter (and I wouldn’t even count on that) but they surely don’t kill.

But they are excellent organic matter to add to the garden.

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