Thursday, March 29, 2012

Planting Dates

A few weeks ago I wrote of the earliness of the season, as evidenced by one of the earliest of the early bloomers, witchhazel. It was already in bloom at Longwood Gardens in Pennsylvania, and the large bush at the front corner of my house has also since come into bloom. A reader, writing from  where temperatures are colder than in my garden, wrote to tell me that he has a witchhazel that started blooming in January! I don’t doubt it.

Witchhazel can mean any one of a few species: Japanese witchhazel (Hamamelis japonica), Chinese witchhazel (H. mollis), vernal witchhazel (H. vernalis), and H. X intermedia, the last of which includes hybrids of the Japanese and Chinese species. Depending on site, species, and variety, the strappy petals might unfold sometime from late fall right into spring. The reader’s plant, the variety, Jelena, at his site probably bloomed earlier than usual this winter. I grow the variety Arnold’s Promise.

Quoting Alfred, Lord Tennyson, “In the Spring a young man's fancy lightly turns to thoughts of” . . . planting, of course. This guy’s thoughts, at least. And especially this year, with spring sprung so early, for now at least. March is a capricious month, with a winter reminder of snow not an impossibility before the month is out.

It was over a week ago that I was visiting Guy Jones’ nearby Blooming Hill Farm and he innocently mentioned to me that he had already sown some lettuce, spinach, and other hardy greens in his fields. Already they were sprouting.

I usually plant by the calendar, with early April being my greens-sowing date. The 70 degree, sunny weather the day after my visit with Guy got the better of me. Out came packets of seeds, a trowel, and a garden rake. I carved four parallel, approximately equally spaced furrows down each of two beds, and into them sprinkled Buttercrunch, Black Seeded Simpson, and Majestic Red lettuce, arugula, and Joy Chen baby bok choy. Covered with soil then firmed with the garden rake, the seeds have all they need to begin sprouting and growing. 
Continued warmth and some water will make things happen. 

I roll my eyes whenever someone tells me that the time to plant peas is on St. Patrick’s Day. Put simply, a gardener in Austin, Minnesota might need a pickaxe with which to plant peas on St. Patrick’s Day while a gardener Sarasota, Florida would need a time machine. Fall would have been the time for planting for the Floridian.

Peas enjoy -- no, need -- cool weather to thrive, which is one reason for planting them early. You want them up, bearing, and then cleared away before hot weather sets in. Heat is not a concern in very northern or coastal regions where summers never get very hot; in such places, peas can even be sown in summer for an autumn harvest.

But back to St. Patrick’s day: That partial myth probably got started because St. Patty’s is the perfect time for planting peas in Ireland. Except far enough south where peas are seeded in autumn for a winter harvest, the correct time to plant peas is when the ground has warmed enough so that the seeds sprout, rather than rot, when they hit the dirt. Pea seeds sprout at about 40 degrees F so if you really want to know when to plant them, stick a thermometer in the ground and wait for that temperature.

  Another way to know when to plant peas is by looking around at what’s blooming. Perennial woody and herbaceous plants are cued into seasonal temperature trends. I used to use forsythia bloom time as my prompt to sow peas but realized for the past few years that those blooms open at about the last, rather than the first, date for pea planting. Just about everybody grows crocus and this little flower is up and out of the ground, and spreading its pretty petals, about when the soil temperature hits that 40 degree mark.

Usually I just play the averages and plant peas on April 1st. But the climate has been a-changin’. I see that my crocuses are up. Hmmm. Just to make sure, I took the temperature of the soil and it’s almost 50 degrees F.  Breaking tradition (mine), I planted peas today. This year, peas on St. Patrick’s Day is the right time for pea planting both here and in Ireland.

Wednesday, March 21, 2012

Coir, A Substitute for Peat

My kitchen isn’t filled with the fragrance and beauty of blooming daffodils, and I have no one to blame but -- no, not myself, but -- the local store where I bought the bulb last autumn. How could I have resisted? Sitting right by the checkout counter of the store was a bucket full of bulbs, each bulb only one dollar and having the makings of fragrance and beauty already locked within.
Yes, “already locked within.” Spring bulbs’ flowers are initiated in the growing season before the flowers appear. The key to unlocking the pleasures lurking within most spring bulbs is cold temperatures. A period of cold weather lets these bulbs know that winter is over and it’s all right to awaken and blossom. Exposure to cold happens naturally outdoors, with the flowers appearing in spring. 
When “forcing” bulbs for early bloom, you trick the bulbs into thinking that winter is over by exposing them to the requisite amount of cold, which varies for different kinds of bulbs. Brought indoors in winter to warmer temperatures, they can then blossom out of season.
The bulb that I bought was a “paperwhite” daffodil, a species (Narcissus tazzeta) that originated in warmer regions of the western Asia. In those warm regions, paperwhites evolved to flower without needing to experience winter cold. So buy one of these bulbs in autumn, pot it up or put its base in water, and bingo, flowers soon appear.
Except for the paperwhite that I purchased. That bulb just kept growing leaves, an indication that last year’s growing conditions were not good enough -- insufficient light, fertility, or water perhaps -- for the bulb to divert energy into making a flower bud.
The present bulb is the second one I got from the same bin this past autumn. After the first one showed no sign of flowers, I went back to the store, explained why, as long as the bulb grows, it should make a flower, and received a second one free of charge. 
I figured the first bad bulb was an aberration. It wasn’t. I’ve been watching leaf after leaf unfurl on the second dud for weeks and weeks.
In an effort to make my farmdening even more sustainable, I’m swearing off peat moss, or hoping to. Peat moss is the partially decomposed remains of plants, mostly sphagnum species. In the garden or farmden, peat moss is very useful for improving soil aeration, and water and nutrient retention. Mostly, these benefits are put to use in potting soils to help roots in their rather limited growing space. My home-made potting mix, which I’ve made for over 30 years, is 1/4 by volume peat moss (the other 1/4s comprised of garden soil, perlite, and compost, and a bit of soybean meal and kelp meal for added nutrients).
Use of peat is unsustainable because its mining outstrips its rate of formation. Peat accumulation can occur at a snail’s pace: an inch or so per thousand years. Peat develops under boggy conditions and to mine it, the bog must be first drained. Air replaces the water and the result is that some of the carbon stored in peat is oxidized to carbon dioxide. And we all know what that does. As a final blow to sustainability, draining and mining peat bogs upsets its unique ecological habitats.
So must gardening and farmdening, both potentially sustainable practices for providing local food that can to be grown with minimal environmental disruption, be wedded to the use of peat moss? Not necessarily.
Other organic materials, such as compost and leaf mold, can fulfill the same functions as peat moss in potting mixes. They have the further advantages of being local and richer in plant food than peat moss. They have the disadvantages that you have to make the stuff, that planning is needed because you have to gather the materials and wait for them to “cook,” and that the final product may not always be consistently the same.
A consistent, commercial peat substitute coming down the pike is coir, a renewable byproduct of coconut processing with characteristics very similar to peat moss. I’ve experimented occasionally with coir over the years and it seemed to work well enough. However, seedlings planted in a recent batch containing coir aren’t thriving.
Anytime a component of a potting mix is changed, changes might also be needed in watering regime or fertilization. My guess is that watering is the problem since my potting mix has plenty of nutrients from the compost and soybean meal, and the symptoms -- poor growth and leaves wrinkly but not off-color -- don’t indicate any nutrient deficiency. The symptoms seem more like those due to poor root growth, possibly from excessive moisture. Or perhaps the soil or compost had some weak root pathogen that’s getting the upper hand.
I need to sleuth out this problem soon because I’m about to make a large sowing of cabbage and its kin as well as peppers and eggplants. On the plus side, all this is some of what makes gardening so interesting.
Any gardening questions? Email them to me at and I'll try answering them directly or in this column. Come visit my garden at

Wednesday, March 14, 2012


Hints of spring are evident even in the dark corners of my barely heated basement. There, buds of potted roses and pomegranate plants are starting to sprout. Some gardeners -- including me -- overwinter potted figs in such places and their early sprouting also can cause concern. So far, only a couple of pomegranates and roses are all that have sprouted from among the 20 or so plants in my basement.

And what are all those plants doing sitting down in my basement? Some, including the pomegranates, figs, and black mulberries, would shrivel up and die from our usual winter cold. The plants are in pots that each autumn are I carry downstairs from outside after their leaves have dropped. Other plants in the basement menagerie are normally cold-hardy, except that they are in decorative pots within which roots, which are not nearly as cold hardy as plant stems, would freeze to death if left outdoors. Larger or better insulated pots would offer roots more protection from cold.

The problem with early sprouting in my basement is that there’s little light down there. New stems on the roses are pale, stretched out, and tender “etiolated). When the plants can finally be moved outdoors, those sprouts, unaccustomed to bright light and wind, will dry out and die. If the plant has not invested too much energy in the sprouts, new sprouts can develop. Ideal conditions, for now, would be cool temperatures and the brightest possible light -- preferably before the new sprouts appeared.
The pomegranates are special varieties so they get first-class treatment: into the greenhouse they go, even though space there is at a premium. The pomegranate buds were just unfolding so the bright light should not burn them.

The roses are more cold-hardy and not so special; they went into the garage where there is some light and, more importantly, it’s a lot colder than the basement. The goal is to hold back growth as long as possible while letting some light fall on what sprouts slowly develop.

The figs in the basement aren’t yet acting like it’s spring. The buds are swelling slightly but are otherwise still folded closed. The goal is to keep them that way as long as possible with minimal watering. 

It’s still too cold in the garage for these plants, whose stems tolerate temperatures down in the ‘teens. Their roots, though, like those of other plants, would be less cold-hardy. I may end up moving the plants in and out of the garage, a sheltered nook of the terrace, and the mud room as temperatures fluctuate in coming weeks. Or perhaps I can find space for them in the greenhouse.

By April, everything in the basement should be fit to face the great outdoors.

Easiest to care for among the subtropical plants in the basement are the mulberries. Anyone who is familiar with mulberries might wonder why I would coddle them in pots in my basement. These mulberries aren’t the run-of-the-mill mulberries that sprout just about everywhere outdoors and bear good-enough tasting fruit that is a bit too cloying.

No, in my basement is a plant of the most delectable black mulberry, Morus nigra, a  species not cold-hardy outdoors here. To my taste, black mulberry -- which the black-colored fruits you see around here are not -- is perhaps the most flavorful of ALL fruits. Each fruit, although the size of a nickel, packs such a whollop of flavor, a congenial mix of sweetness and tartness, that you’d think it came from a fruit the size of an apple.

Two other mulberries down in the basement are there because I’m not yet sure just how cold-hardy they are and because, if cold-hardy, I still have to figure out where to plant them. Gerardi Dwarf is possibly a variety of white mulberry (M. alba), a very variable Asian species well-established in eastern U.S. and often bearing black-colored fruits also. (This variety is sometimes listed as Morus macroura.) Whitman Farms (, where I got my plant, states that the fruit of this particular variety is almost as good as black mulberry, the species, and the plant grows only 6 feet high, which makes picking and protecting from birds easy.
The other plant, Kokuso mulberry (M. latifolia) is supposed to be very cold-hardy and, as rumored on the fruit “grapevine,” very tasty. The plant is semi-dwarf and the  fruit, like the others, is dark.

The thing that makes all these mulberries easy is that they are late to awaken in spring. Mulberry’s generic name, Morus, comes from the Latin word mora, meaning delay. This sluggish start in the spring usually saves mulberry flowers from being nipped by late spring frosts, which makes mulberries bear very reliably and, as described in Fruit and Its Cultivation (1919) by Thomas William Sanders, “the wisest of trees.”

Thursday, March 8, 2012


One perk of writing a book about pruning (The Pruning Book) is that I get sent a lot of pruning tools to try out. The pruning shears hang on a row of wooden pegs near my back door, loppers hang on pegs in the garage, and hand saws fill a five gallon bucket. All the big-name brands are represented, from ARS to Bahco to Corona to Felco to Fiskars to Silky. With many models of each brand of tool at my fingertips, it’s easy to tell which ones I like the best. They are the ones for which I reach most frequently.
With the coldest part of winter behind us (and even that not very cold), it was time for me start pruning. Today’s sunny weather and temperatures in the 40s made pruning an enjoyable excuse to be outdoors. Into my leather holster went an ARS hand pruning shears. Sometimes, if I need to cut stems that are a bit beefier, I’ll grab instead my Felco shears. Or, for lighter pruning, my Pica shears. All are excellent although the ARS shears have the edge for me.
Into a back pocket went a small folding hand saw. Many manufacturers make hand saws, and if they have so-called turbo, Japanese, tri-edge, or three-angled blades, they’re all equally good.
In my hand, I carried my Fiskars PowerGear® 2 Bypass 17 inch Lopper. What’s nice about this tool, which can cut through stems up to an inch or so thick, is their light weight fiberglass composite handles and their gearing mechanism which triples the cutting power.
Carrying those three tools, I could cut just about anything needing to be pruned. 
Watching tiny, green leaves push up through the soil never ceases to amaze me, even after watching it happen for decades. And it’s all the more amazing with certain seeds, such as onions. It must be that I was scarred years ago by having a difficult time getting them to germinate. Well, I sowed them in the greenhouse a couple of weeks ago and they’re up and growing strongly. Most of them, at least.
My failure with onions years ago was due to old seed, and old for onion seed means anything more than a year old. Lettuce seed, in contrast, is one of the longest-lived of vegetable seeds and keeps up to 6 years. Here’s the life expectancy for other common vegetable seeds: 5 years for cucumber, endive, muskmelon, and radish; 4 years for beet, Brussels sprouts, cabbage, chard, eggplant, kale, mustard, pumpkin, tomato, turnip, and watermelon; 3 years for bean, broccoli, carrot, Chinese cabbage, pea, and spinach; 2 years for sweet corn, leek, okra, and pepper; and, along with onion, 1 year for parsley and parsnip. Under poor storage conditions -- moist and warm, like my garage in summer -- longevity is decreased.
Still, it seemed like such a shame to throw away good onion seed only a year old. So, in the seed flat a couple of weeks ago, a sowed one row of one-year-old onion seed alongside the rows of fresh onion seeds (and one row of leeks).
Confirmed: onion seed isn’t worth sowing after one year. In the seed flat are five neat rows of narrow, green sprouts and one barren row.
Few seeds have as short a life as onion. More astounding is the longevity of some seeds, such as the 10,000 year old lupine seed that germinated after being taken out of a leming burrow in the Yukon permafrost. Just think: This same species was up and growing when humans first crossed the Bering Land Bridge, and saber-toothed cats and woolly mammoths may have brushed up against its leaves. Except that the story of the 10,000 year old lupine seed turned out to be apocryphal, as confirmed by radiocarbon dating.
The record for seed longevity is, in fact, 2,000 years and held by a date palm grown from seed recovered from an ancient fortress in Israel. But a recent discovery, once confirmed, will break that record by a long shot.
A kind of campion seed (Silene stenophylla) found buried, this time in a squirrel burrow, in Siberian tundra could very well be 32,000 years old. The seed has been grown into a charming, white-flowered plant.
Some coaxing was needed to get that original, 32,000 year old seed to sprout. A few cells, removed from the placenta, were grown under sterile conditions on a specially concocted growth medium. Once cells had multiplied sufficiently, the growing medium was altered to induce leaves, stems, and roots, and eventually the plants were robust enough to be planted in soil. The plant flowered and set seed, which germinated readily to produce more seedlings.
I wonder what seed has the shortest longevity. It’s not onion. Seeds in the family Tillandsioideae, related to pineapple, probably hold the record, with a viability of 4-6 weeks.

Thursday, March 1, 2012


  Hot off the press!!! My new book, Grow Fruit Naturally: A Hands-On Guide to Luscious, Homegrown Fruit (The Taunton Press). The book for anyone who wants to pick luscious fruit right from their own sunny balcony, suburban lot, or farmden. Sure, growing your own fruit will save money but -- even better -- your home-grown apples, blueberries, peaches, or oranges will be the best you’ve ever tasted and won’t be doused with toxic sprays. Available (signed copies) at
Gardening’s newest wunderkind is biochar, touted as being able to preserve soil fertility almost indefinitely while, at the same time, making a dent in carbon dioxide production that leads to global warming. Biochar’s origins go deep into the Amazon, where soils are naturally low in fertility. There, explorers recently discovered regions of dark, fertile soil that were deliberately created through the addition of charred wood. Such soils are also found where vegetation was naturally or deliberately burned over.
Let’s go back to high school chemistry for some understanding of biochar. Biochar is, essentially, charcoal that is made by partial burning of wood, straw, corn stalks, or other organic materials. Charcoal, especially the activated charcoal used in chemistry, is riddled with tiny holes that can adsorb nutrients. (A single gram of activated charcoal has enough internal surface area to cover a tenth of a football field!) In the soil, biochar, similar to activated charcoal, can adsorb nutrients, provide habitat for soil microbes, and increase aeration.
Biochar is very resistant to decomposition, which leads to its other touted benefit, carbon sequestration. It locks up organic carbon, formed when plants take in carbon dioxide for photosynthesis, so that it’s not re-released into the atmosphere as carbon dioxide when dead plants decompose. 
Let’s say you had a pile of wood that you could grind up and make into compost, or that you could burn to make biochar. Which use is better? In soil, both compost and biochar would cling to nutrients. Compost would enrich the soil with nitrogen and, very important, provide food for beneficial soil microbes which would, in turn, feed plants. Microbial byproducts also help give soils that crumbly structure loved by plants and sought after by good gardeners. Many of the benefits of compost accrue as it decomposes, which is why it needs constant replenishment. Biochar has the leg up on longevity, some kinds lasting hundreds of years.
Compost offers little in the way of carbon sequestration, with the bulk of its carbon eventually turning to carbon dioxide that puffs up into the atmosphere. But, to repeat, many benefits of compost accrue precisely because it does decompose and eventually turn to mostly carbon dioxide and water. Decomposition of wood, straw, or any other organic material reflects microbial feeding. (What we eat also eventually turns mostly to carbon dioxide and water.)
So which is the better use of organic wastes? Compost is definitely good for the soil. Ongoing research will tell whether also using a bit of biochar is also worth the trouble. For more about biochar, see
Turning to more immediate concerns . . . My hopes to be eventually and happily drowning in fragrant lilies were dashed by the blue flowers recently brightening the sunny window “greenhouse” in my basement. 
For explanation, let’s backtrack to last autumn. Summer’s lily flowers -- intoxicatingly fragrant, large white trumpets of the variety Casablanca -- were long gone but the plants’ tawny flower stalks and seed capsules were still evident. Wouldn’t it be awesome, methinks to myself, to make every August a heady month by overrunning part of the garden with Casablanca? 
Digging into the dirt around those tawny, old lily flowerstalks easily turned up a slew of healthy little bulbs, which I potted into cell packs and put near that cool, basement window. Leaves appeared a few weeks ago, foreshadowing oodles of lily flowers a couple of years hence. 
It was not to be: Those small bulbs at the base of the lily stalks were NOT lily bulbs; they were chionodoxa (glory-of-the-snow) bulbs.
Not that chionodoxa isn’t a pleasant little flower, and it appears at a time of year when any flower is most welcome. But it ain’t no lily.
I should also explain about that sunny window “greenhouse” mentioned above. Like many older homes, mine used to have a metal Bilco door that opened into the barely heated basement. Much of the heat in the basement was lost due to the conductivity of and small openings in the Bilco door. Those openings also provided entryway for an occasional snake or other small or thin creature.
Many years ago I decided to make use of the southern exposure of that Bilco door. So I ripped out the door, enlarged the opening with additional concrete blocks and a (semi-)waterproof coating of ThoroSeal. I then built a cedar frame into which I slid two large sheets of Exolite, a double-walled polycarbonate plastic material used for greenhouses.
Voila! I had a place to keep plants cold, but not frigid, and sunny. Temperatures in that old doorway hover near freezing on cold winter days and nights. The location has proved ideal for overwintering geraniums, semi-hardy cyclamens, subtropical pineapple guavas and an olive tree, and various other plants that need light and need or tolerate cool winter temperatures. Chionodoxa also does very well there.