Phenology – What happens when

Flowering Purple (or Red) Dead Nettle, with honeybee.Credit Kathryn Simmons
Flowering Purple (or Red) Dead Nettle, with honeybee.
Credit Kathryn Simmons

For ten years I have been keeping phenology records, as a guide to when to plant certain crops, and as a way of tracking how fast the season is progressing.

Phenology involves tracking when certain wild and cultivated flowers bloom, seedlings emerge, or various insects are first seen. These natural events can substitute for Growing Degree Day calculations. Certain natural phenomena are related to the accumulated warmth of the season (rather than, say, the day-length), and by paying attention to nature’s calendar you will be in sync with actual conditions, which can vary from year to year, and are changing over a longer time-scale..

Many people know to sow sweet corn when oak leaves are the size of a squirrel’s ear. By this point, regardless of date, the season has warmed enough to get oak leaves to that size, which happens to be warm enough for sweet corn seed to germinate and grow well. Some people transplant eggplant, melons and peppers when irises bloom; sow fall brassicas when catalpas and mockoranges bloom; and know to look for squash vine borers laying eggs for the two weeks after chicory flowers. Some transplant tomatoes when the lily of the valley is in full bloom, or the daylilies start to bloom.

Lilac is often used to indicate when conditions are suitable for various plantings:

  •   When lilac leaves first form, plant potatoes
  •  When lilac is in first leaf (expanded), plant carrots, beets, brassicas, spinach, lettuce
  • When lilac is in early bloom, watch out for crabgrass germinating
  • When lilac is in full bloom, plant beans, squash, corn. Grasshopper eggs hatch.
  • When lilac flowers fade, plant cucumbers.

Also, recording the dates of the same biological events each year can show longer term climate changes. In Europe, 500 years of recorded dates of grape harvests provide information about summer temperatures during that time. Project Budburst is a citizen science field campaign to log leafing and flowering of native species of trees and flowers across the US each year. Each participant observes one or more species of plant for the whole season.

 Here’s our Twin Oaks Phenology Record so far:

(c) Pam Dawling, 2013

Event 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 Notes
Crocus blooming 26-Jan 25-Jan 6-Feb 10-Feb 28-Feb 17-Feb 30-Jan
Chickweed blooming 8-Feb 1-Jan 5-Mar 10-Feb 13-Mar 19-Feb 13-Feb 15-Feb
Robins arrive 27-Feb 31-Jan 20-Jan 26-Feb 2-Mar 14-Feb
Henbit blooming 14-Mar 7-Mar 12-Jan 6-Jan 7-Feb 20-Feb 22-Mar 2-Mar 15-Feb 15-Feb
Daffodils blooming 17-Mar 9-Mar 7-Mar 1-Mar 22-Feb 3-Mar 5-Mar 15-Mar 3-Mar 17-Feb Plant potatoes
Dead-nettle blooming 18-Mar 6-Mar 7-Mar 8-Mar 14-Mar 9-Feb 24-Feb 13-Mar 21-Jan 22-Feb 10-Feb
Spring Peepers first heard 4-Mar 11-Mar 10-Mar 3-Mar 3-Mar 6-Mar 11-Mar 28-Feb 23-Feb 5-Mar Plant peas
Overwinter Grasshoppers seen 26-Feb 4-Apr 25-Feb
Maples Blooming 10-Mar 6-Mar 15-Mar 12-Mar 28-Feb
Dandelion blooming 16-Mar 16-Mar 24-Jan 1-Jan 3-Mar 17-Mar 9-Mar 8-Mar 19-Mar Sow beets, carrots
Forsythia blooming 13-Mar 12-Mar 28-Mar 10-Mar 23-Mar 13-Mar 17-Mar 21-Mar 15-Mar 12-Mar 15-Mar Plant peas. Crabgrass germinates.
Peach blooming 15-Mar 25-Mar 26-Mar 25-Mar 13-Mar
Cabbage White Butterfly 25-Mar 20-Mar 7-Mar 8-Mar 11-Mar 6-Apr 24-Mar 12-Mar 14-Mar Dutch white clover blooms
Harlequin bugs 10-Apr 13-Mar 26-Mar 12-May 16-Apr 29-Apr 14-Mar
Johnny Jump-up blooming 16-Mar 30-Mar 14-Mar 20-Mar 3-Apr 17-Mar
Flowering Cherry blooming 27-Mar 4-Apr 3-Apr 1-Apr 6-Apr 25-Mar 17-Mar 18-Mar 20-Mar
Asparagus spears 6-Apr 4-Apr 4-Apr 5-Apr 6-Apr 6-Apr 21-Mar 19-Mar
Redbud blooming 5-Apr 13-Apr 9-Apr 3-Apr 2-Apr 7-Apr 9-Apr 7-Apr 4-Apr 19-Mar Expect flea beetles
Smartweed germinating 15-Apr 10-Apr 15-Apr 6-Apr 11-Apr 1-Apr 23-Mar 20-Mar <149 GDD base 48F
Lambsquarters germinating 20-Mar 20-Mar <150 GDD base 48F
Violets blooming 29-Mar 26-Mar 28-Mar 6-Apr 22-Mar 20-Mar
Morning Glory germinating 27-Apr 10-Apr 3-Apr 26-Apr 24-Apr 25-Apr 22-Mar >349 GDD base 48F
Tiger Swallowtail 19-Apr 29-Mar 15-Apr 16-Apr 18-Apr 10-Apr 28-Mar
Apples blooming 18-Apr 20-Apr 14-Apr 7-Apr 12-Apr 28-Mar
Dogwood (Amer.) full bloom 5-Apr 21-Apr 13-Apr 28-Mar Plant peppers; soil 65 F
Strawberries bloom 13-Apr 11-Apr 14-Apr 12-Apr 4-Apr 2-Apr 15-Apr 6-Apr 8-Apr 30-Mar
Lilac full bloom 16-Apr 20-Apr 21-Apr 22-Apr 19-Apr 21-Apr 14-Apr 18-Apr 1-Apr Plant beans, squash
Crimson Clover blooming 29-Apr 2-May 16-Apr 22-Apr 23-Apr 27-Apr 18-Apr 25-Apr 4-Apr
Whippoorwill first heard 1-May 22-Apr 15-Apr 24-Apr 17-Apr 25-Apr 8-Apr 14-Apr 5-Apr
Galinsoga germinating 1-May 22-Apr 16-Apr 20-Apr 6-Apr
White Oak “squirrel’s ear” 20-Apr 26-Apr 23-Apr 26-Apr 25-Apr 14-Apr 23-Apr 12-Apr Plant sweet corn
Tulip Poplar blooming 2-May 10-May 3-May 26-Apr 3-May 6-May 26-Apr 28-Apr 17-Apr Plant sw corn 200 GDD base 50F
Ragweed germinating 20-Apr 16-Apr 25-Apr 26-Apr 21-Apr Plant sw corn 200 GDD base 50F
Last Frost 24-Apr 4-May 3-May 1-May 8-May 17-Apr 19-May 10-May 14-Apr 25-Apr Average 4/30 (10 yrs)
Fireflies 7-May 2-May 1-May
Colorado Potato Beetle adult 22-May 3-May 7-May 29-Apr 27-Apr 3-May 25-Apr 2-May
Strawberries ripe 10-May 17-May 12-May 10-May 7-May 15-May 3-May 10-May 7-May
Purslane germinating 26-May 8-May 22-May 5-May 20-May 15-May 8-May
Baby Grasshoppers 12-Jul 30-Jun 26-Jun 17-Jun 16-May
Cicada first heard/seen 14-May 5-Jul 3-Jul 29-Jun 17-May
Hardneck garlic mature 14-Jun 19-Jun 13-Jun 5-Jun 4-Jun 30-May 9-Jun 11-Jun 6-Jun 31-May
Foxgloves bloom 6-Jun 11-Jun 8-Jun Bean beetle eggs hatch
Bean Beetle eggs 4-Jun 16-Jun 10-Jun 6-Jun 20-Jun Hatch when foxgloves bloom
Japanese Beetle first seen 16-Jun 21-Apr 15-Jun 20-Jun 29-Jun 21-Jun 850 GDD (base 50F)
“June” Bugs first seen 5-Jul 11-Jul 2-Jul 12-Aug 10-Jul 30-Jun 29-Jun 30-Jun 23-Jun
Corn Earworm first seen 28-Jul 8-Jul 12-Jul 10-Jul 14-Jul 150-490 (base 54F)
Fall Dead-nettle germinating 1-Sep 20-Aug 30-Aug 20-Aug 16-Aug 20-Aug 15-Aug 29-Aug 18-Aug Plant spinach
Fall Henbit germinating 28-Aug 20-Aug 29-Aug 18-Aug
Fall Chickweed germinating 7-Sep 7-Sep 5-Sep 6-Sep Plant spinach
First Fall Frost 3-Oct 6-Nov 27-Oct 13-Oct 29-Oct 20-Oct 19-Oct 23-Oct 30-Oct 22-Oct Average 10/22 (9 yrs)
Harmonia Ladybugs migrate east 18-Oct 12-Nov 21-Oct 27-Oct
Garlic planted (hardneck) 25-Oct 20-Oct 9-Nov 3-Nov 11-Nov 1-Nov 5-Nov 11-Nov 15-Nov 6-Nov Soil temp 50 F
Event 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 Notes

Ordering seeds! Seed Viability and Varieties New to us

I’ve been busy putting our seed orders together. As we grow so many different crops, it’s quite a time-consuming process. And I hate to buy too little and be out in the field on planting day, looking at an almost empty packet. Equally, I hate to buy too much, which either wastes money (if we throw the extra away), or else causes us to risk sowing seed that really is too old, and won’t do well. I keep a chart of how long different types of seed last:

Seed Viability

(From Sustainable Market Farming, (c) Pam Dawling, New Society Publishers, 2013)

     

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   “Opinions vary a bit about how many years seeds of different vegetables are good for. The fuller story is that storage conditions make a big difference. You can make your own decisions, weighing up the information supplied, your knowledge of how carefully you stored the seeds, the information on each packet about percentage germination when you bought it, and the economic importance to you of that particular crop. If you always transplant lettuce, as I do, you can risk one of your four varieties in that sowing coming up poorly, and just plant out more of the other three if it fails. Many seed catalogs include information about seed longevity, and so does Nancy Bubel in The Seed Starters Handbook.

www.chelseagreenFrank Tozer in The Organic Gardeners Handbook has a table including minimum, average, and maximum.

A simplified version is as follows:

  • Year of purchase only: Parsnips, Parsley, Salsify, and the even rarer Sea Kale, Scorzonera
  • 2 years: Corn, Peas and Beans of all kinds, Onions, Chives, Okra, Dandelion, Martynia,
  • 3 years: Carrots, Leeks, Asparagus, Turnips, Rutabagas
  • 4 years: Spinach, Peppers, Chard, Pumpkins, Squash, Watermelons, Basil, Artichokes and Cardoons
  • 5 years: most Brassicas, Beets, Tomatoes, Eggplant, Cucumbers, Muskmelons, Celery, Celeriac, Lettuce, Endive, Chicory.”

Rather than deteriorating with age, some very fresh seed has a dormancy that needs to be overcome by chilling (lettuce). Other seed contains compounds that inhibit germination. These can be flushed out by soaking in water for about an hour (beets).

Another of the challenges with seed ordering is converting between grams, ounces and seed counts. Here’s a helpful table of 1000 Seed Weight for 13 crops.

Our main seed suppliers are FedcoJohnny’s and Southern Exposure. Fedco has great prices, especially on bulk sizes, great social and political commentary in the catalog, and no glossy pages. Johnnys has some good varieties that Fedco doesn’t, and a ton of useful information tucked away on their website. Southern Exposure is best on southern crops and heat tolerant varieties which we can’t expect seed companies in Maine to specialize in. Plus, SESE are my friends and neighbors.

This year we are trying some new varieties. Generally we like to have some reliable workhorses that we know well, and trial a few new things, especially if we hear our favorite varieties are no longer available. Last year our Nadia eggplant couldn’t cope with the heat. For a while in early summer they didn’t grow at all – no new flowers, never mind new fruit. So next year, alongside Nadia I’m trying 3 that should deal better with heat. Florida Highbush is open-pollinated, from the Seed Savers Exchange. Epic and Traviata are hybrids from Osborne Seeds.

Epic eggplant from Osborne Seeds
Epic eggplant from Osborne Seeds
Traviata eggplant from Osborne Seeds
Traviata eggplant from Osborne Seeds
Florida High Bush eggplant from Seed Savers Exchange
Florida High Bush eggplant from Seed Savers Exchange
Sugar Flash Snap Peas from Osborne Seeds
Sugar Flash Snap Peas from Osborne Seeds

I also bought some Sugar Flash snap peas from Osborne. We have been big fans of Sugar Ann, but I’ve heard Sugar Flash is even better on flavor, yield and harvest period. We’re going to find out!

For a couple of years we really liked Frontier bulb onions as a storage variety for this climate and latitude (38N). Frontier disappeared from the catalogs of our usual suppliers and we tried Gunnison and Patterson. This year – no Gunnison! And we didn’t get a good test of Patterson last year, as we failed to weed our onions enough, after an initial enthusiastic good go at it. We were looking again at Copra, one we grew some years ago (before we found Frontier). I lucked out when I decided to see if Osborne had Gunnison, while I was shopping there. they didn’t, but they had Frontier! And then when I was shopping at Johnny’s, I found they did have some Gunnison for online sales only. So I ordered those too!

We’re also trying Sparkler bicolor sweet corn from Fedco and a drying bean I won’t name, as the seed is in short supply. And this year we’re hoping Red Express cabbage will prove to be a reliable little worker. We used to like Super Red 80, but had several years of poor results. Since then, none of the other red cabbages we tried have satisfied us in terms of size, earliness, productivity and flavor.

West Indian Gherkin Seeds (Cucumis anguiria) from Monticello
West Indian Gherkin Seeds (Cucumis anguiria) from Monticello

After a few years of poor pickling cucumbers, we’re going outside the box and trying West Indian Gherkins from Monticello, where they were grown by Thomas Jefferson (and some of the enslaved people, no doubt). These are not closely related to actual cucumbers, but are used similarly. I saw them growing in the Monticello garden when I was there for the Heritage Harvest Festival in September, and they are certainly robust and productive in hot humid weather. We’ll see how the pickles turn out!

My only other “impulse buy” was the Salanova Lettuce new at Johnny’s. They are 6 varieties of head lettuce designed to be used for salad mix at a single cutting. Quicker than  snipping rows of baby lettuce with scissors. More fun than plain lettuce heads. They are loose heads of small leaves in various shades of green and red, and two “hairstyles”: frizzy and wavy.

Salanova Lettuce from Johnny's Seeds
Salanova Lettuce from Johnny’s Seeds

Winter Hardiness

It can be hard to find out just how cold a temperature various vegetable plants can survive. Reading books written in different parts of the country can be confusing: “survives all winter” is one thing in the Pacific Northwest and another in Montana. So for some years I have been collecting data and exchanging information with my friend and neighbor Ken Bezilla at Southern Exposure Seed Exchange. Each winter I try to record what dies at what temperature. Below is my current list, which should be treated as a work in progress.

Your own experience with your soils, microclimates and rain levels may lead you to use different temperatures. If you have data from your garden, please leave a comment. Likewise if you have found particular varieties to be especially cold-tolerant, I’d love to learn more. Central Virginia isn’t the coldest spot in the US, but if I can grow something without rowcover, I’m happy to hear it!

Here’s our temperature list at which various crops die:

 35°F (2°C):  Basil.

32°F (0°C):  Bush beans, cauliflower curds, corn, cowpeas, cucumbers, eggplant, limas, melons, okra, some Pak Choy, peanuts, peppers, potato vines, squash vines, sweet potato vines, tomatoes.

27°F (-3°C): Most cabbage, Sugarloaf chicory (takes only light frosts), radicchio.

 25°F (-4°C): Broccoli heads, chervil, chicory roots for chicons, and hearts, probably Chinese Napa cabbage (Blues), dill, endive (hardier than lettuce, Escarole more frost-hardy than Frisée), annual fennel, large leaves of lettuce (protected hearts and small plants will survive even colder temperatures), some mustards and oriental greens (Maruba Santoh, mizuna, most pak choy, Tokyo Bekana), onion scallions, radicchio. Also white mustard cover crop.

22°F (-6°C): Arugula, Tatsoi. (both may survive colder than this.) Possibly Chinese Napa cabbage (Blues), Maruba Santoh, Mizuna, Pak Choy, Tokyo Bekana with rowcover.

20°F (-7°C): Some beets, cabbage heads (the insides may still be good even if the outer leaves are damaged), celeriac, celtuce (stem lettuce), some corn salad, perhaps fennel, some unprotected lettuce – some OK to 16°F (-16 °C), some mustards/oriental greens (Tendergreen, Tyfon Holland greens), radishes, turnips with mulch to protect them, (Noir d’Hiver is the most cold-tolerant variety).

17°F (-8°C): Barley (cover crop)

15°F (-9.5°C): Some beets (Albina Verduna, Lutz Winterkeeper), beet leaves, broccoli leaves, young cabbage, celery (Ventura) with rowcover (some inner leaves may survive at lower than this), cilantro, endive, fava beans (Aquadulce Claudia), garlic tops may be damaged but not killed, Russian kales, kohlrabi, perhaps Komatsuna, some covered lettuce, especially small and medium-sized plants (Marvel of  Four Seasons, Rouge d’Hiver, Winter Density), curly leaf parsley, flat leaf parsley, oriental winter radish with mulch for protection (including daikon), large leaves of broad leaf sorrel, turnip leaves, winter cress.

12°F (-11°C): Some cabbage (January King, Savoy types), carrots (Danvers, Oxheart), multi-colored chard, most collards, some fava beans (not the best flavored ones), garlic tops if fairly large, most fall or summer varieties of leeks (Lincoln, King Richard), most covered lettuce (Freckles, Hyper Red Rumpled Wave, Parris Island, Tango) , large tops of potato onions, Senposai, some turnips (Purple Top).

10°F (-12°C): Beets with rowcover, Purple Sprouting broccoli for spring harvest, Brussels sprouts, chard (green chard is hardier than multi-colored types), mature cabbage, some collards (Morris Heading), Belle Isle upland cress, some endive (Perfect, President), young stalks of Bronze fennel, perhaps Komatsuna, some  leeks (American Flag), Oriental winter radish, (including daikon), rutabagas, (if mulched), tops of shallots, large leaves of savoyed spinach (more hardy than flat leafed varieties), tatsoi, Yukina Savoy. Also oats cover crop.

5°F (-15°C): Garlic tops if still small, some kale (Winterbor, Westland Winter), some leeks (Bulgarian Giant, Laura, Tadorna), some bulb onions (Walla Walla), potato onions and other multiplier onions, smaller leaves of savoyed spinach and broad leaf sorrel.

0°F (-18°C): Chives, some collards (Blue Max, Winner), corn salad, garlic, horseradish, Jerusalem artichokes, Vates kale (although some leaves may be too damaged to use), Even’ Star Ice-Bred Smooth Leaf  kale, a few leeks (Alaska, Durabel); some onion scallions (Evergreen Winter Hardy White, White Lisbon), parsnips, salad burnet, salsify, some spinach (Bloomsdale Savoy, Olympia, Tyee). Also small-seeded cover crop fava beans.

Even Colder: Overwintering varieties of cauliflower are hardy down to -5°F (-19°C).

Many of the Even Star Ice Bred varieties are hardy down to -6°F (-20°C).

Walla Walla onions sown in late summer are hardy down to -10°F (-23°C).

Winter Field Peas and Crimson clover (used as cover crop) are hardy down to -10°F (-23°C).

Hairy vetch and white Dutch clover cover crops are hardy to -30°F (-34°C)

Sorrel and some cabbage (January King) are said to be hardy in zone 3, -30 to-40°F (-34 to -40°C)

Winter wheat and winter rye (cover crops) are hardy to -40°F (-40°C).