Birch Meadow Greenhouses

Every year I hear the same comment...

“sure, the baskets look great in the greenhouse, but they won’t grow like that outside"

Well I'm here tell you that they can, and anyone can do it.

There are simply some basic guidelines that have to be adhered to, and we are going to go over them in detail, step by step.

The photos used in this presentation are baskets and planters that have been growing outside all season, some only meters away from 24 hour traffic. Some are growing in areas so hot, there are times the planters are too hot to touch when we lean over to weed. Still others have no shelter from the sun, wind, rain or vandalism they endure on a daily basis. All plant displays in these photos are designed, planted and maintained by myself or my staff.

As we cover these 5 easy steps for growing giant baskets, we will see how these 5 simple steps can relate to all aspects of gardening. 

Bigger is better.

The larger the pot, the larger the flower basket why?

Bigger pots require less maintenance, which results in larger, better quality plants. Plants that are left dehydrated on a regular basis spend all their energy trying to rejuvenate the growth they already have.

Giant hanging baskets should be a minimum of 14” in diameter.

Moss baskets require much more maintenance than fiber or plastic pots if they are to be grown in the sun. Moss baskets were an innovation for areas with high humidity and limited exposure to drying winds. In all my travels I have yet to see a commercially grown town or city moss basket in peak growing condition. They simply dry too quickly.  If you can monitor your baskets continuously throughout the day, or if you have a very sheltered shady location, then by all means enjoy.

Oak barrels are great for large displays. Don’t forget to drill holes in the bottom for drainage. Oak barrels are designed to seal when wet! I have seen floating flowers more than once in barrels with no drain holes.

This basket was over 7 feet from top to bottom. Our preferred size of basket to plant in, is the 16” fiber basket with steel hoop and hanger. Plenty of root ball space for a dynamic display, and large enough to almost eliminate double watering in consecutive 35 degree temperatures.

A 14” basket will grow close to the same size however if there are more than 3 consecutive days of 30 degree plus temperatures we may water twice, depending  on size of plant material and day length. That of course being the number one reason we have now changed up our baskets to the 16” size. Do remember however, our baskets are generally subject to a lot harsher conditions than that of the average homeowner, unless their baskets are away from the shelter of their home or on the lake shore. 

Prepared container potting mix is a must.

This should really be called choosing the “potting medium” as container potting mix actually contains no soil at all; it is primarily composed of peat moss.

Never use straight garden soil or straight peat moss for hanging baskets. Straight peat moss is much too acidic to grow most plant material, while straight garden soil is much too heavy to be used in containers.

A good potting medium will have a blend of peat moss, vermiculite and perilite and will also have its PH amended usually with limestone. This should be listed on the bag under composition or ingredients. Perilite is the small hard white grit which is added for drainage and air porosity. Vermiculite is the soft shiny particles which hold fertilizer and micronutrients in the potting medium. Flower beds with poor, heavy soil should be amended with fiber only. Never add sand to heavy soil, unless you are road building.

This particular flower bed used to take three of us 8 hours to hand cultivate. Every year we would remove buckets of heavy clay soil and add bags of peat moss mixes. Today we can actually cultivate this bed quite quickly with a small rototiller.   Plants will root much Faster, and grow with much better results.

I cannot over emphasize the importance of good soil maintenance.

All of our planters have been amended with potting soil. We continue to add small amounts of mix every year.

Adding manure of any kind to your garden plot is a means of adding fiber--And weed seeds, and e-coli bacteria, and fungal pathogens.

Some container growing mediums contain water crystals that absorb water upon wetting, then releases small amounts after the container has dried. Studies have shown that they do in fact do as they claim, however, these crystals will readily absorb water but when it comes to releasing it, they tend to be slight stingy. This puts the plants through a temporary stress period before releasing moisture. The down side to this of course, plants that are continually stressed set more seed. Hence more deadheading. They are also more likely not to reach maximum size.

However at the other end of the scale, these set-backs are probably minimal compared to a planter that has been left in extreme heat and wind for an extended period of time without any hydration at all. A gardener must examine what the watering guidelines are that he or she has set for themselves to determine if this is the choice of medium for them to use.

Know your exposure.

When a tag suggests “full to part shade”,

Plants should not be exposed to the hot afternoon sun. These plants ideally prefer the cool morning and late evening sun. Avoid the noon till 4 o'clock exposure.

Begonias, Fuchsias, and Bacopa are probably the most popular shade plants.

In addition to the familiar non-stop begonia, rex begonias are making quite an impact in the bedding market. These decorative foliage varieties offer a huge assortment of shapes and color.

Heuchera is another shade or sun plant which conveniently will stuff and grow anywhere, A well behaved tidy plant, this tender perennial will add unique color shading and markings to almost any container.

Coleus has definitely come a long way in the past few years. Bred only for the shade garden for so many years, the new hybrids offer striking colorful displays for either sun or shade.

Lobelia seed varieties must be grown in the shade.

More combinations for the shade

German ivy is an incredibly fast growing vine which can also be grown as a house plant. Predominately for the shade, this vine has been known to grow in full sun with ample water supply. Due to its ability to establish itself quicker than other companion plants, it may need trimming every now and then to keep it from overtaking entire combinations.

Variegated Jacobs Ladder adds an interesting touch, don’t be afraid to add perennials to your pots or baskets.

Although most perennials will not bloom throughout the whole summer, some offer very different foliage displays not available in everyday annuals.

These baskets always get quite a lot of attention.

They are our 16” fiber baskets planted with 4 Dragon Wing Begonias and 2 Dappled Light Creeping Charlie. This year’s baskets were planted with two more Dragon Wings each which gave them a larger red canopy on top.

Dragon wing begonias are appropriate for the sun or the shade however, when planted in this type of hanging basket combination they will dry too quickly and should be kept from the hot afternoon sun as there is an enormous amount of plant material in these baskets.

The Richardson basket faces north and receives all the wind exposure Mother Nature can send, yet it stands up remarkably well. These baskets must be watered before 9:00 a.m. in order to sustain moisture throughout the hot days. The county baskets are sheltered from the hot afternoon sun, along with north and west winds, making them easier to manage.

Solenia begonia baskets are pictured here on the left, dragon wing planters to the right.

The Solenia Begonia will perform equally well in sun or shade. This delicate looking Solenia flower surprisingly stands up very well to the elements however does prefer warmer temperatures when first planted. Our unseasonably cold June and July of 09 did not agree with our Solenia baskets. These photos were from the 08 crop.

Sun Exposure

The term “sun” refers to a minimum 6 hours of direct sun. The following are suggestions for sun exposure.

One of the most frequently asked question in the greenhouse would be “What is the difference between Waves and Supertunias?

Both of these varieties are considered vegetative, which means they are extremely aggressive, spreading Hybrid varieties.

The biggest difference between Waves and the rest of the vegetative petunias is that the Wave series is propagated from seed, while the rest are propagated through cuttings.

Waves are the only vegetative petunia to set seed true to the parent plant. Other varieties either do not set seed at all or only a limited amount that does not grow true to the parent.

All vegetative varieties offer different color choices in singles, doubles, bi-colors, mini flowers etc. Some different series include, Surfinias, Jamborees, Sangunas, Blanket flowers, just to mention a few. Different Plant Propagators have different names for the varieties they breed. For example, Proven Winners breed Supertunias, Surfinias and Blanket Flowers while Syngenta breeds Jamborees and Sangunas.

The name game can start to become a little overwhelming after awhile but all the consumer really needs to look for is the phrase “vegetative spreading". That will ensure you have petunias aggressive enough to produce giant baskets.

These baskets are “Giant Pink” Supertunias. Giant Pink would be the color, Supertunia would be the series.

This is probably one of the most aggressive vegetative varieties. The flowers are huge, putting on a dynamic display of color. The plant itself is probably one of the fastest and largest growing vegetative varieties on the market today. Finishes long before most of its competitors.

This is a 14” fiber pot with only 4 plants in each basket. There is a reason they refer to them as Supertunias. 

Bordeaux is the color, Supertunia the series.

This is a well behaved color choice.

This plant basket does not have the long trailing characteristic of the Giant Pink but rather a perfect round ball shape. Think support bra and you’ll understand where I’m coming from. Don’t be fooled, although a different shape this color will become equally giant in size.

Always tidy, never deadheaded.

Always plant aggressive plant material in your vegetative Petunia combination baskets. This is not the place to grow small dainty plant material.

Look for other vegetative plant varieties, such as Verbena, Bacopa, Osteospermum, or Lobelia. Remember to watch for the words vegetative or spreading in the plant descriptions. Check your tags closely, don’t be fooled by names, Mini Blue Vein Petunia does not refer the final size of the plant as you can see in this photo. They are referring to the size of the flowers itself.

Plant height will refer to the height above the basket. Spread will refer to the length below the basket. “Full sun” refers to a minimum of 6hrs of direct sunlight.

When planting grasses in baskets, you may have to cut your petunias back somewhat to let your grass become established. If planting 4” pots of petunias into your baskets, plant 5” or 6” grasses. The grass in this basket is Stipa or more commonly called Pony Tail Grass.

I sometimes have to wait for the photo shoots to end before I can water this street in the morning.

These deck pots have purple fountain grass and lime green potato vines which work nicely in large containers. The potato vine loves the heat that this south facing wall reflects. It is nicely protected from the winds also. Potato vine is not a good choice for windy areas, as the foliage will tear and become ragged looking in the wind.

The town’s most photographed flower bed.

There is now a new series of Supertunias called the Vistas.

This series of petunia will withstand wind and rain unlike any other. A very tight growing super aggressive plant. For those of you that have extremely windy locations, such as lake shore exposure, this series can’t be beat. Our commercial baskets are now predominately planted with this series, specifically for this reason.

They come in three colors, Fuchsia, Bubblegum and Silverberry. This bed is planted with Vista Bubblegum and Vista Fuchsia. These flowers not only make perfectly round hanging baskets, they are a sure way to cover a lot of ground space quickly with flowers. The fountain grass gives a waterfall effect to this floral display.

Argyranthemum Butterfly is a fast growing, continuous blooming yellow daisy. Butterfly is the color name of this daisy.

We deadhead this particular flower to promote a fresh looking display.

Blocks of solid color create more curb appeal than general mixes.

Adding giant grasses to a container arrangement definitely makes a statement. Pampas grass can become huge overtime creating a magnificent display.

This grass had been wintered in our greenhouse for 5 years, despite its size we failed to see much for plumes. After 5 years we only ever saw 4 or 5 plumes. Our summer season is just not long or hot enough for them to bloom properly.

This year we are going to dress these planters up a notch. We have some rare centerpieces I purchased last summer that I have been growing specifically for this particular location. You will have to watch and see!

Feeding your baskets

Container mediums are peat moss based, therefore have no natural nutrients.

Baskets must have a regular feeding program for optimum results. When transplanting any kind of plant material, a high phosphorous fertilizer is recommended. This will be a fertilizer with a higher middle #, such as 10-52-10, 9-45-15, even 5-15-5. All of these combinations contain roughly three times the amount of phosphorous ratio to nitrogen and potash.  Nitrogen of course being your first # and potash being your last.

Please note the fertilizers I have listed are not for “growing on.” They are strictly for rooting purposes. Once your plants have rooted to the outside of their pot, this fertilizer should be discontinued.

All of our aggressive plant material requires large amounts of nitrogen to keep them growing and blooming. The more foliage, the more blooms. Nitrogen is the key to promoting strong stems and lush green foliage. Too much phosphorous will result in considerably smaller plants with fewer blooms. Products advertized as “bloom” with higher middle numbers such as 10-52-10 are not good choices for growing on.

Read the label; know what your #s are saying. The best fertilizers for these potted plants are 20-8-20, 19-2-19, 20-10-20 or even 20-20-20.

Slow Release vs. Water-soluble.

Slow Release is a pellet form of fertilizer designed to release nutrients as it breaks down over time. Fertilizer should be added at time of planting by scratching into soil just under surface. If baskets are already rooted then simply spread pellets on surface under leaf material, taking care not to put pellets into direct contact of plant stems. Ideal growing conditions of warm temperatures and ample moisture will activated the breaking down process.

Water soluble fertilizers are just that, fertilizers that completely dissolve in water.

Mix fertilizer in warm water to ensure all salts are dissolved. Never add fertilizer water to a basket with undissolved salts. (fertilizer) and never add undiluted compost tea. This is a sure fire way to burn plant roots. Biggest advantage to water soluble fertilizer is you always know how much feed your plants are actually getting.

Watering practices--this where most gardeners fall victim to misjudgment.

Every time it rains and I’m standing out on the street corner, watering wand in hand, I hear time and time again, why are you watering can’t you see it is raining.? Actually no, I forgot my rain detector at home, but thanks for pointing that out.

First of all, the amount of water that these baskets require after a full day of hot sun is a lot more than what 5mm of rain can provide. Figure it out. If your basket requires 3 liters of water per watering, how much would it have to rain to put 3 liters of water into that pot? A lot. So a good rain after a full day in the hot sun will not provide enough water to hydrate it for the whole day. If the rain stops at noon, the sun comes out and the wind starts to blow. This, is a recipe for disaster.

However, if the basket is watered thoroughly in the morning and there is rain and no drying temperatures that same day, the basket would not need to be watered the following day.

The only sure way to see if a basket needs water is to lift it, if the basket is heavy, you can probably skip the watering. If the basket is light in weight, water it till it starts to drip. When foliage is hydrated, it is full of water. Water of course is quite heavy in fact eight pounds per gallon to be exact. Peatmoss will hold a substancal amount of water when hydrated also. Combine the two together and in a 16" pot you can have a difference of 10-12 lbs in the weight of a basket depending if it is wet or dry. A sure fire way to decide on whether to water or not.

Ideally baskets should be watered in the morning before they start to dry. Try to avoid watering in the evening. Plants will have already gone into a stress mode prior to watering if it has been a hot summer day.

Rehydrating the neglected basket:

First, remove basket from direct sun. Immerse the entire root ball in a container of water to soak for at least one hour. This will allow the peat moss fibers to absorb the water slowly and swell again. If your basket is too large to accommodate this procedure, then water every 15 minutes for the first hour, every thirty minutes for the following hour. The basket should be retaining moisture by this time. Do not return basket to full sun location for 24 hours.

Although misjudgments can be made, remember, an ounce of prevention is worth a pound of cure. Your baskets will love you for it!