Jim Shields' Garden Notes
Blog Home | Archives | Category Index | Links | About This Blog | Shields Gardens
Blog Home : February 2007

- Effects of Cold

Since around Christmas, the temperatures have been consistently below average for this time of year. It appears we have not had a winter spell of real cold as severe as this since around 1998. When the temperatures remain near and below freezing without intervening thaws for long periods of time, the frost line moves steadily deeper into the ground. Temperatures dropped to -2°F (-19°C) this morning under crystal clear skies. Winds of 20 to 25 m.p.h. (ca. 30-40 km/hr) insured that the frost line in the ground dropped even deeper.

Because of this, I suspect that we are going to see losses in semi-hardy bulbs this winter. I expect to lose Gladiolus and Crinum bulbs planted outdoors in exposed locations. Zantedeschia planted outdoors in open areas last Fall will likely not survive. Daffodils are up 3 to 4 inches, with buds. They should survive the temperatures, but the buds might be damaged.

We have trays of 4- to 8-month old Clivia seedlings under lights in the basement that need to be repotted from their initial 3-inch square by 4 inches deep seed starting pots into 5½-in. sq. by 6-in. deep pots (ca. ½ gallon size). It's been too cold to risk taking them outdoors to the big greenhouse for repotting. Seeds ripening on the Clivia plants need to be collected, brought up to our house, and planted in the 3 x 3 x 4 inch pots.

We don't keep flowering plants inside our home, because the pollen tends to set off my asthma. I do have a few hybrid amaryllis (Hippeastrum hybrids) in bloom in the south window of the bedroom. I keep the pollen removed as fast as it ripens, so we get to enjoy the flowers for a longer period than if they could accidentally be pollinated. Sometimes I even store it dried and frozen.

Two hybrids that we bought last year, 'Chico' and 'Reggiae', look like Hippeastrum cybister. Pollen of one Dutch type put on 'Chico' does not seem to have set any pods. I suspect these are triploids, from crossing tetraploid Dutch hybirds with the H. cybister, a diploid species. They are unique and a nice contrast to the usual big hybrids (which I love!)

- Clivia Seedlings

First the weather report: Cold but sunny! There is a layer of about 5 to 6 inches of snow on the ground. High temperatures during the days have been below freezing for over two weeks now; several days in a row, the morning lows were below 0°F. This discourages outdoor work, or even trekking back to the big greenhouse. Mike Sherley's crew did plow a path back to the big greenhouse (the Clivia House, greenhouse #4) when they cleared the driveway earlier this week. I'll try to drive back today and see if I need to get the Kubota out and scrape some more snow away for a turn-around and a path to the greenhouse door.

Snow in the Backyard
The Clivia House in a field of snow. Taken from the living room window.

We are late getting the heat in the Clivia House warmed up to promote flowering. When it is this cold, it is at best a waste of money to turn the thermostats up. It might even be futile! We need to move the temperatures from their current 45-55°F range (nights-days) to the 60-65°F range if we want bloom scapes to begin growing. I think our bloom time this year will be late, probably peaking in early April instead of the usual mid-March time, because of this extension of the winter cold regime in the Clivia House.

Here in our home, some of the Clivia seedlings growing under lights in the basement are getting big enough to move back to the big Clivia greenhouse. A few have been sitting too long with their feet wet, sitting in trays and crowded under the lights. I probably should give them more individual attention, but there tend to be soooo many of them!

Young Clivia seedlings in trays
Trays of Clivia seedlings planted one year ago.

A few will now get individual attention. Once we get them back in the big greenhouse, Irma will pot the largest of them up into the next size pots, 5½-inches square by 6 inches deep. From that point on, they will all get individual attention, some soon moving on to 1-gal. pots, others sitting in the 5½-inch pots for a year or more.

Genetic Variation

Any plants grown from seeds will show individual variations, in size, vigor, rate of growth, etc., even as seedlings. Later on as they mature, a few will probably reach bloom size in 3 years or less, most in 4 to 5 years, and a few will linger on longer, if they ever grow large enough to flower. When doing multigenerational line breeding, we need to select first the most vigorous plants. Then we can select further for flower color, form, bud count, or whatever seems more important to us at the time.

We have some seedlings starting from seed from an un-named Conway Peach pollinated with a Victorian Peach®. Almost all have unpigmented (i.e., green) leaf bases. Most open-pollinated Solomone Cream seedlings have green leaf bases. Seedling from open-pollinated seeds on Solomone Pinks are a mix of plants, some with green and some with red leaf bases. Might the pink parents be split for yellow? It's hard to know at this point, but in a few years we should be able to see the answer to that with our eyes.

Take care, join us again in a week or so, and use the link just below to send us any comments or quetsions you may have. If your comments strike me as interesting, I will probably include them in this blog in the future, with due credit to their writer.

- Blizzard of 2007

It started snowing here in the wee hours of this morning, and it's still snowing and blowing. Cities around us, like Carmel and Kokomo, have 12 inches of new snow on the ground, so far. The winds have been blowing at 25 - 30 m.p.h. all day, so I don't know how anyone finds a good spot to check the snow depth. The town of Westfield is keeping the road out in front reasonably clear, but our driveway is covered and drifted in areas.

Snow and the greenhouses, Feb. 2007 This shows the near end of Greenhouse No. 1 on the left and the end of Greenhouse No. 2 in the center rear. In the foreground, the snow-filled path from GH No. 1 around to the steps down into GH No. 2.

This is the deck outside the bedroom, showing the drifts near the steps leading down to the side yard. Snow drifted on the deck, Feb. 2007

The counties all around us on the west, north, and east have all declared snow emergencies. Hamilton county, where we are, has not done so. Still, the State Police are warning everyone in central Indiana to avoid going anywhere if they don't absolutely have to. We haven't budged out of the house except to clear a snow path on the deck down into the yard for the dogs to use. The path won't stay cleared.

In January, 1978, we had a comparable blizzard, with an official snow depth of 12+ inches and strong winds. The city of Indianapolis was shut down for two days then, as I recall anyway. This is as bad, but Indianapolis has not had to declare an all-out snow emergency, as they did in '78.

The only greenhouse I can get into now is Number 1, the lean-to Everlight Home Greenhouse attached directly to our home. I had shoveled a path to Greenhouse No. 2 earlier this afternoon, but that has long since blown shut, full of more snow. I have remote thermometers working in both 1 and 2, so I can monitor the inside temperatures in both. So far, so good. GH No. 1 is about 54°F. GH No. 2 has been at or above 45°F so far today, and the plants in No. 2 can easily take temperatures near freezing: Lachenalia, Haemanthus, Scadoxus. By the way, I can see from here that the Scadoxus puniceus are in full bloom in GH No. 2.

Irma was busy planting Clivia seeds today, and will be again tomorrow. We took advantage of the pre-storm warm weather (up to 36°F) on Saturday and Sunday to move flats of the larger, 1-year old, seedlings from the lights in the basement back into GH No. 4. That gives us some empty space under the lights for these new flats of seeds.

We don't throw away any Clivia seeds. We always get more seeds from un-pollinated plants than from those we hand-pollinate. Our biggest batches this time are from the lot of stock plants of Solomone Light Yellows and of Solomone Pastels. We will have to grow those seeds all the way to flowering to be sure what we are getting from them.

I am hoping for more Clivia blooms this year, since I feel that we have had the routine in GH No. 4, the big Clivia House, pretty near optimal for the past 12 months. I'm especially looking forward to seeing blooms on the Solomone "Deepest Reds" that we bought for breeding use in 2005; none of that batch has bloomed yet.

We have several peaches that I hope to see blooming this spring: Solomone's 'Apricot', a few 'Victorian Peach'® plants from Victor Murillo, and a couple of Conway's famous peaches, like 'Tessa' and 'Ellexa'. I'm extremely eager to make crosses between these various peaches, to see someday if any are related.

My other passion is for the so-called "Parti-Color" (Conway) or "Watercolor Washed" (Solomone) types. We have a few of each here for breeding purposes, and I want to cross the Solomone "Watercolor Washed" X Conway "Parti-Color" and see what we get. If they do bloom this spring, you can get back to me in about 5 or 6 years for the results!

- Day After the Blizzard

The snow has stopped! The sun is shining! There is almost no wind. The blizzard is over. The temperature is about +8°F.

After shoveling a path across the deck and down the steps, for my geriatric dogs to go in and out, I grabbed a yardstick and went out the back door. I walked a large loop around the backyard. I probably got 100 feet from the back (west side) of the house, and measured every 5 to 10 feet, trying to avoid the obvious drifts.

I measured from 11 to 17 inches of snow depth, with probably a median as well as an average depth of 14 inches. It is really hard to walk in snow that is 14 inches deep, at least if you're my age, shape, and size. We are definitely going to wait here at home until Mike Sherley comes to plow out our driveway.

- Two Days After the Blizzard

The sun is shining again today. Our driveway was plowed out yesterday evening, so we can get away from the house now. We still can't get back to the big greenhouse, at least not without wading through 300 feet of 14-inch deep snow. I'm not ready to try that just yet.

Snowy back yard and the big greenhouse. The snow covered back and the Clivia House. My footprints in the snow are where I measured snow depths of about 14 inches.

Dutch type Lemon and Lime hybrid. Inside our home, there is a bright spot: the "Lemon and Lime  hybrid amaryllis (Hippeastrum) is in bloom. This is not the small-flowered form that I was familiar with, but appears to be a hybrid with Dutch ancestry in it. It came with two others that were labeled the same but which flowered pink.

The weather forecasters are talking about a shift in the jet stream in about a week, and then temperatures here in the 40s F. I can't wait!

- Potpourri

Plant terminology

In the Alpine-L list today, Carlo Balistrieri and Wally Wagner suggested people get the book "Plant Identification Terminology: An Illustrated Glossary" (Paperback) by James G. Harris and Melinda Woolf Harris if you want a good guide to technical plant terminology. Thee are about 200 pages, with illustrations. I most often have to consult a reference for terms relating to leaf shape; I have trouble remembering the differences between "linear," "lanceolate," and "obovate" leaves! This sounds like the book to get.

Potting Mixes

We grow all our container bulbs in a gritty mix. While we originally used regular Pro-Mix BX, we have recently switched to using only the Pro-Mix BX Biofungicide®, which contains a selected strain of Bacillus subtilis bacteria that kills fungi without attacking the plant roots. Pro-Mix BX Biofungicide is highly recommended!

Gritty Mix: We use the following for growing all our container bulbs. Pro-Mix BX Biofungicide + brown builders' sand + granite chick starter grit (ca. 1/8-in. mesh) at ratios of 2 : 1 : 1 by volume. These components are mixed thoroughly; break up any lumps by hand that resist the mixing process. For small amounts, you can do this in a 5-gallon bucket. We use a 20-gallon portable electric concrete mixer and mix 16 gallons at a time. We store the mix in 30-gal. plastic trash cans.

Sandy Mix: We use a slightly different mixture for starting seeds of most bulbs. Pro-Mix BX Biofungicide + brown builders' sand at a ratio of 2 : 1 by volume. This is what we start Clivia, Haemanthus, Hymenocallis, Nerine, and Scadoxus seeds on.

Daylily Seeds

It's time we planted our daylily seeds from last summer. We always try to start them indoors during the winter, so we can transplant the seedlings outdoors into the seedling bed sometime during the summer. We should have started them a month or two ago, but finding time was a challenge.

We plant them in straight Pro-Mix BX Biofungicide®, in 4-inch square pots or bigger, with up to 16 seeds in a 4-inch pot or up to 25 seeds in a 5-inch square pot. Fill the pots with the Pro-Mix, firm it down well, add seeds, and cover the seeds with about ½ inch of Pro-Mix. We spray to wet the mix thoroughly from above, then put the pots in leak-proof trays and place them under the fluorescent lights in the basement. The fluorescent lights are on automatic timers and are run 16 hours per day. We water the pots from below, by just pouring water into the trays. Do NOT let the seeds dry out!

We feed the seedlings regularly with dilute solutions of soluble fertilizer, when we water. Scotts makes a variety of water-soluble plant foods sold in small quantities under the Peters name. For larger amounts, they use the "Jack's Professional" name or the Scotts name. We use one with N-P-K = 20-10-20 (nitrogen-phosphate-potash) that they call "Peat-Lite"®.

Climate Change

There is a note in the "Science in the News" e-mail newsletter from Sigma Xi today that January 2007 was the warmest January on record. The Sigma Xi newsletter quotes from The Seattle Times newspaper. World-wide, January was 1.53°F warmer than the average or one-quarter degree warmer than the previous record for January.

In spite of a colder than normal February, the world is warming steadily. It seems to bother some folks that a local area, like North America for instance, can be colder than usual while the planet is growing steadily warmer. Let's see if I can explain the apparent paradox in understandable terms.

First, the heat balance. The planet gets its heat mainly from the Sun. Some solar radiation comes in through the atmosphere and warms the surface of the Earth. The rest of it is reflected back out into space, lost to us forever. In an equation, Total Solar Radiation = Absorbed Heat + Reflected Radiation. Rearranged,

Absorbed Heat = Total Solar Radiation - Reflected Radiation

The amount reflected and lost is regulated by the atmosphere. Carbon dioxide (CO2) and methane (CH4) are called "greenhouse gases" because they absorb some of that radiation that would otherwise be lost back out into Space. That is why the earth is getting warmer -- we are producing lots of gases that trap heat from the Sun, heat that would otherwise be lost into outer Space.

So how can a hotter Earth produce a colder February?

The climate engine of the Earth -- the air and the water -- operate a little like a steam engine or a gasoline engine. The more energy (heat) you put into it, the harder it can work. It's that simple!

The extra heat we are trapping in Earth's atmosphere and oceans is forcing the Climate Engine to drive the weather to more extreme conditions. Global Warming is going to mean hotter weather, colder weather, wetter weather, and drier weather, all at the same time. A warmer January globally is followed by a colder February locally in eastern North America. It's all part of a hotter, more energetic Earth.

- Hints of Spring

How can I call this note "Hints of Spring" when there is still a layer of snow on the ground a good 15 inches deep? Because the long range forecast calls for highs of 50°F or higher by the coming weekend!

Clivia House Temperatures

Yesterday, we raised the temperature settings on the environmental controller in the Clivia House (greenhouse no. 4) part way. We also hooked up the feeder and turned on the drip irrigation system. We are ready for Spring.

When the sun came out, even with the lower heating and cooling settings, the temperatures inside still were in the 70s F. Yet I have noticed only one pot with scapes starting: a yellow miniata hybrid from South Africa. I might not have noticed those buds, deep down in the center of the plant, except for having wanted to retrieve an umbel of nearly ripe berries.

I am going to be on pins and needles for the next month or two, waiting to see which plants will finally bloom. Have they been resident in my greenhouse long enough? Did I give them good enough care last summer? Did I finally get the temperature regimen in the greenhouse right this winter?

Plant Conservation

A recurring topic in the lists dealing with plant species is what to do about preserving those species that are disappearing in nature. There are some very diverse opinions on this subject, to put it mildly. Currently, these is such a discussion, a very good discussion, going on in the TooColdForCactus list on Yahoo Groups; you can find it at: http://groups.yahoo.com/group/Toocoldforcactus/. The good folks in this list are mainly interested in cactus that are hardy other places than the deserts of the southwestern USA.

There are two main approaches to preserving rare plant species:

Some proponents of in situ conservation tend to get red in the face when confronted with the notion of ex situ conservation. I'm a supporter of ex situ conservation and propagation in certain cases, but I agree that in situ is always the best first choice if it looks like it has any chance of succeeding. On the other hand, I consider in situ conservation exclusive of additional ex situ propagation to be short sighted and -- in some cases -- merely self-serving of the personal/professional interests of certain professional conservationists. (That ought to offend somebody!)

Botanical Books

In today's Alpine-L messages, Diane Huling recommends another book for looking up technical terms in botany: "The Gardener's Dictionary of Horticultural Terms" by Harold Bagust, pub. 1992, ISBN 0-304-34106-1. She says, "lots of illustrations."

- Foggy Bottom

Heavy low fog here this morning! After several days of spring-like weather, temperatures in the high 40s F and a couple of nights above freezing, it got cold last night. The result was dense freezing fog this morning. It is still there around my place, but it is fading south of here in the northern rim of Indianapolis.

Drainage in Pots

Susan Bergeron of Ontario province, Canada, posted an experiment that she did recently. The original posting (with a typo, she tells me) was to the Daylily E-mail Robin at <http://listserv.icors.org/SCRIPTS/WA-ICORS.EXE?LIST=DAYLILY>. Susan gave me permission to repost it to other lists, and I also corrected the original typo in the re-posted version. That should be in the Pacifc Bulb Society list archives at <http://lists.ibiblio.org/pipermail/pbs> where it would be under my name as poster, topic is Potting Mix and Drainage.

The gist of her experiment was to demonstrate that a normal potting mix retains more water when layered over a course drainage material like polystyrene foam peanuts than when the pot contains nothing but the potting mix. In the pot with only potting mix, the mix retained 105 ml of water per cup of mix. In the pot with a drainage layer in the botton, the mix itself retained 135 ml per cup of mix, almost 30% more water.

This elegant little kitchen experiment clearly demonstrates what experts have been trying to tell us for years: coarse crocks or pot chips below the potting mix impede rather than promote drainage.

So the moral is, use the same potting mixture throughout the whole flower pot.

- Drainage Mythology

Here is some more comment on gardening mythology. The first is more on potting and drainage, this time comments from Paul Cumbleton, of Middlesex, UK. Paul works at the Royal Horticultural Society Wisley Garden, and the comments below are from his introductory lecture to new garden trainees. Paul posted these originally to the Pacific Bulb Society list, and has given me permission to reproduce them here.

Paul Cumbleton's Comments

I was so pleased to see the discussion on this and especially delighted to see the correct answers being given. The old myth of adding a layer of grit or other material to the bottom of a pot "for drainage" seems never to die, despite the science that disproves its efficacy being known for over a hundred years.

I have regarded it as something of a personal mission to correct this old misunderstanding. Each intake of trainees here at the RHS Wisley Garden where I work has a lecture from me specifically on this subject trying to explain the science behind drainage in reasonably simple terms. If you will excuse a long posting, I here present an edited version for those of you who are interested. If this is not your thing, please just scroll on down! Note, although these notes talk about alpines, the same things apply to bulbs or any other plants requiring good drainage:

What is Important in a Compost Mix?

In the wild, many alpines grow in situations where water drains away very quickly and easily - this is known as "sharp" drainage. This results in many air spaces around the roots. When growing in a pot, we need to provide similar conditions and make a mix that while holding sufficient water to supply the plant, drains excess water very rapidly to leave lots of air spaces. Before looking at how to achieve this, let's first ask:

Why is it important to have lots of air spaces?

Roots not only take up water, they take up and need oxygen too. Roots are normally covered by a thin film of water. Oxygen has to diffuse across this before it can enter the root. Oxygen diffuses through water relatively slowly. So the thicker the layer of water around the root, the longer it takes oxygen to diffuse through it to get to the root, which may result in the roots being starved of oxygen. Without it, they cannot metabolise and perform their functions - one of which is to take up water. This explains why the symptoms of plants being over-watered or under-watered are the same: If under-watered there is insufficient water to supply the plant and so it wilts. If over-watered, there is plenty of water around but the roots cannot take it up due to being short of oxygen. So the result is the same - the plant may be sitting in water but it wilts because it cannot take the water in.

The reason for going into all this is that plants vary on just how sensitive they are to the amounts of oxygen in the growing medium - and alpines are among those plants that require a high degree of aeration. This is why when growing alpines we aim to produce a mix which is very free-draining, so leaving plenty of air spaces in the medium. The percentage of the volume of a medium that contains air after it has been saturated then allowed to drain is called the Air Filled Porosity (AFP). For the majority of plants, a figure between 10% and 20% AFP is aimed at; for alpines this figure needs to be at the higher end of this range or even above.

So when we say a plant needs good drainage, it may be more informative to say that what they need is good aeration (which is created by good drainage).

What factors affect drainage?

1. Pore Size - Pores are the spaces between (and within) the solid parts of a medium and they contain the air and water required by the plant for growth. Pores vary enormously in size. The relative numbers of large and small ones, the way they are grouped and how interconnected they are will determine the rate of water movement through the mix and also determine how much air and water are retained. It is these factors that you can alter by adding drainage material such as grit, and the extent of the effect will vary depending on the particle size of the grit you use and the amount you add to a mix.

The most important factor is the relative proportion of big pores to little ones. This is because of a key point: small pores hold onto water more strongly than large ones - due mainly to capillary action. This means that small pores (called micropores) retain water, which leaves no room for air, while big ones (called macropores) tend to drain most of their water leaving air in its place. It follows that fine sands are not suitable as drainage components- the fine particles simply fall into the larger air spaces, clogging them up and producing smaller pores that hold on to water - in other words you get poorer drainage, the opposite of what you want. So, use only coarse grits as drainage material - in practise, this means ones with most of the particles larger than 1.6 mm diameter.

2. Quantity of Grit used - If you add a very small amount of grit to a medium it will not help the drainage, it will simply displace some of the medium. For grit to work as a drainage medium there must be enough of it so that it exceeds what is called the threshold proportion. The threshold proportion is where there is just enough grit that the particles touch each other. At this point, the pores between the grit are still filled with soil and humus and no new macropores have been created. More grit must be added to further "dilute" the medium so it exceeds the threshold. At this point, new macropores are created that drain readily and provide aeration. In practice, most alpine growers use between 30% and 50% (by volume) of grit in their mixes to achieve this.

3. Pot Depth and Perched Water Tables - When you water into a pot and excess starts coming out the bottom, it is coming out due to a mix of gravity pulling on it and the weight of water above pushing down on it (the "hydraulic head"). As water drains, there is a point at which gravity or the hydraulic head are insufficient to push any more water out. So at the bottom of each pot there is a layer where ALL the pores are filled with water. This is called a perched water table. This is true of all pots whatever mix it contains - at the bottom of every pot there is always a perched water table. Wouldn't it be good if we could prevent this?

This brings us to the old myth. "Put a layer of grit or other coarse material at the bottom of pots and containers to provide drainage". You will hear such advice repeated again and again in books, on websites and TV programmes. Materials recommended for such use may include gravel, grit, sand, broken up clay pots or polystyrene bits, all to be added "for drainage". If you ask the person giving this advice as to EXACTLY why they think this will work, they often don't know - it's just something they have been taught or read about and they have never stopped to think why it might work. If they do have an explanation, it is usually to point out that coarse materials have large air spaces that drain more easily than small air spaces. This is of course correct as we saw earlier. HOWEVER this applies to the materials ALONE. They don't stop to think what happens if you start putting materials in layers. What actually happens is that drainage is HINDERED by this practice and water tends to accumulate at the boundary between the two layers. This happens for two reasons:

a) As we learned earlier, small pores hang on to water more strongly than large ones. Because of this, when you have a medium with smaller pores above one with larger pores, the water has difficulty crossing the boundary. There is insufficient "strength" in the larger pores to pull the water out of the smaller ones above where they are held more strongly by capillary action. So instead of the water draining evenly from the pot, it drains to the interface between the two layers then slows down or may even be stopped altogether until a sufficiently large hydraulic head has built up again to force it across the boundary. This of course means when the compost above is completely saturated! Since the stated goal for using a layer of coarse material is  to improve drainage", it is ironic that this practise actually causes the very state it is intended to prevent!

b) Secondly, the natural "perched water table" we learned about has now been forced to form higher up the pot giving what is called a RAISED perched water table. This leaves even less of the volume of the pot which contains well-drained and well-aerated compost.

There is however a way to remove the perched water table from a pot, so that the whole volume of the pot is well drained: Plunge the pot in a sand plunge. For this to work, ensure that the compost in the pot makes good contact with the sand beneath. This has the effect of greatly increasing the length of the pot so that the perched water table doesn't form until the water reaches the bottom of the plunge. Sometimes people put a piece of broken pot over the drainage hole of clay pots - but this will break the continuity between the compost and the plunge so this will not then work. A good modern alternative is to cover the drainage hole in clay pots with a piece of plastic net. This will help stop compost trickling out but not entirely break the continuity between compost and plunge. Removing the perched water tables from pots is probably the most important function that a plunge serves, so it is strange that this aspect is rarely mentioned these days when the functions of a plunge are discussed.

Thus endeth the lesson...!

Good growing everyone

Paul Cumbleton
RHS Wisley Garden

Thank you, Paul, for your definitive comments on drainage.

Blog Home | Archives | Category Index | Links | About This Blog | Shields Gardens

Easy Blogs - Evaluation edition
Last revised on: 23 February 2007
© Page and Contents Copyright 2007 by Shields Gardens Ltd. All rights reserved.