Only January, Yet Already Time to Sow Seeds?



20180103 ENG, &

It’s only January! Surely it’s too soon to sow seeds? Source:, & mzayat. com

The new year has barely begun, yet now and over the coming month it’s already time to start certain seeds indoors.

This is a very select group of especially slow-to-mature plants. January is far too early for most seeds (think March or April instead), but you need about four to five months of indoor culture to bring the following plants to the right state of growth for outdoor planting.

  1. Agastache (Agastache foeniculum)
  2. Datura (Datura metel)
  3. Fairy Snapdragon (Chaenorrhinum origanifolium, syn. glaerosum)
  4. Lisianthus (Eustoma grandiflora)
  5. Spike dracaena or cabbage palm (Cordyline australis, syn. indivisa)
  6. Tritome (Kniphofia )
  7. Tuberous Begonia (Begonia × tuberhybrida)

No Easy Feat!


Artificial light is almost essential for seeds started in January. Source: laidbackgardener. blog

Starting seed in January in the Northern Hemisphere is not simple. The days are short, the sun is weak and, in many areas, the weather is gray more often than sunny, meaning light is seriously lacking. Also, temperatures in front of the average windowsill are cool, yet almost all seeds need warmth—and fairly even temperatures—to germinate well. As a result, you pretty much have to start these under artificial lights, such as fluorescent or LED plant lights, and in the warmest part of your home.


Germinate the seedlings under glass, possibly over a heating pad, as above. Source:

Always start winter-sown seeds “under glass” (under some sort of transparent covering) to maintain high humidity and stable temperatures and in a room that is at least moderately warm (72 to 75˚ F/21 to 24˚ C) or place the seed containers on a heating pad (one specifically designed for plants). Use a timer to set the day length of your lamp at 14 hours to simulate the long days of summer and place the containers of freshly sown seeds about 6 to 12 inches (15 to 30 cm) below the lamp. Now, wait patiently for germination to occur. (One reason that certain seeds need early sowing is that they are slow to germinate.)

Seeds That Require a Cold Treatment


Many tree, shrub and perennial seeds need a cold treatment before they will germinate. Source: laidbackgardener. blog

January (or December or February) is also a good time to start seeds that need a cold treatment (cold stratification) to germinate well. This group includes most trees and shrubs from cold and temperate climates, but also many perennials and even a few annuals.

These seeds will not germinate until they have received a given number of days of cool, moist conditions, from as little as one or two weeks to four months or more, information you would (hopefully) find on the seed pack.

The number of weeks given is the minimum requirement for that species, but there is no maximum. So, if you keep seeds that need, say, a two-week treatment in the cold for two months, that’s not a problem. That’s nice to know, because the information on the minimum cold treatment for seed X is not always available, especially for seed you harvested yourself. If you don’t know, I suggest giving seeds of perennials a six to eight-week cold treatment: that’s usually enough. For trees and shrubs, I’d recommend three months.

Simply sow these seeds in a container as you would any other, then seal them inside a clear plastic bag and pop them into the refrigerator or cold room for at least the minimum number of weeks. Afterwards, move them to a warm, well-lit spot, on a windowsill or under lights, for germination to start.

100 Seeds That Need a Cold Treatment

Here are 100 plants that germinate best with a cold treatment (there are thousands of others!). Check the seed envelope or the seed supplier’s web site for more information.

  1. Abies (fir)
  2. Acer (maple, mosts species)
  3. Aconitum (aconite)
  4. Alchemilla (lady’s mantle)
  5. Allium (ornemental onion)
  6. Amelanchier (serviceberry)
  7. Aquilegia (columbine)
  8. Asclepias (milkweed, some species)
  9. Astrantia (masterwort)
  10. Baptisia (false indigo)
  11. Buddleia (butterfly bush)
  12. Caltha (marsh marigold)
  13. Caryopteris (bluebeard)
  14. Cercis canadensis (redbud)
  15. Chelone (turtlehead)
  16. Cimicifuga (bugbane)
  17. Clematis (clematis)
  18. Cornus (dogwood)
  19. Corydalis (fumitory)
  20. Delphinium (delphinium)
  21. Dicentra spectabilis, now Lamprocapnos spectabilis (bleeding heart)
  22. Dictamnus (gas plant)
  23. Dodecatheon (shooting star)
  24. Echinacea (purple coneflower)
  25. Eremurus (foxtail lily)
  26. Eryngium (sea holly)
  27. Eupatorium (Joe Pye weed)
  28. Filipendula (meadowsweet)
  29. Forsythia (forsythia)
  30. Fragaria (strawberry)
  31. Fuchsia (fuchsia)
  32. Gentiana (gentian)
  33. Geranium (perennial geranium, cranesbill)
  34. Goniolimon (German statice)
  35. Helianthemum (rock rose)
  36. Helianthus (perennial sunflower)
  37. Heliopsis (false sunflower)
  38. Helleborus (Christmas rose)
  39. Hemerocallis (daylily)
  40. Heuchera (coral bells)
  41. Hibiscus moscheutos (perennial hibiscus)
  42. Hypericum (St. John’s wort)
  43. Iberis (perennial candytuft)
  44. Ilex* (holly)
  45. Incarvillea (hardy gloxinia)
  46. Iris (iris, many species)
  47. Kirengeshoma (waxbells)
  48. Knautia (knautia)
  49. Lathyrus (perennial sweet pea)
  50. Lavandula (lavender)
  51. Leontopodium (edelweiss)
  52. Lobelia (hardy lobelia)
  53. Lonicera (honeysuckle)
  54. Macleaya (plume poppy)
  55. Magnolia* (magnolia)
  56. Malus (apple, crabapple)
  57. Mazus (creeping mazus)
  58. Mertensia (Virginia bluebells)
  59. Muscari (grape hyacinth)
  60. Myrrhis odorata (sweet cicely)
  61. Nepeta (catmint)
  62. Oenothera (evening Primrose)
  63. Opuntia* (beavertail cactus)
  64. Paeonia* (pivoine)
  65. Penstemon (beard-tongue)
  66. Persicaria (fleeceflower)
  67. Persicaria orientalis, syn. Polygonum orientale (kiss-me-over-the-garden-gate)
  68. Phlox (phlox)
  69. Physalis (Chinese lantern)
  70. Picea (spruce)
  71. Platycodon (balloon flower)
  72. Primula (primrose)
  73. Pulsatilla (pasque flower)
  74. Quercus (red and black oaks)
  75. Ranunculus (buttercup)
  76. Ratibida (prairie coneflower)
  77. Rosa (rose)
  78. Rudbeckia (black-eyed Susan)
  79. Sambucus (elderberry)
  80. Sanguinaria (bloodroot)
  81. Sanguisorba (burnet)
  82. Saponaria (soapwort)
  83. Saxifraga (saxifrage)
  84. Scabiosa (pincushion flower)
  85. Sedum (stonecrop)
  86. Sempervivum (houseleek)
  87. Sidalcea (prairie mallow)
  88. Staphylea* (bladdernut)
  89. Stokesia (Stokes’ aster)
  90. Syringa (lilac)
  91. Thalictrum (meadow-rue)
  92. Tiarella (foamflower)
  93. Tricyrtis (toad-lily)
  94. Trillium* (trillium)
  95. Trollius (globeflower)
  96. Tsuga (hemlock)
  97. Vernonia (ironweed)
  98. Veronica (speedwell)
  99. Viola (violets)
  100. Vitis (grape, some species)
*Some species in this genus require a double cold stratification: that is, two cold treatments separated by warm one, to germinate well. Try two to three months of cold followed by two months of warmth, then again two to three months of cold. When you expose them to warmth after these repeated treatments, most will germinate quite readily.

Good growing!20180103 ENG, &

Seeds to Sow in Early January


20160101D.jpgThe New Year that has barely begun marks the beginning of a new gardening season too. Already the days in the Northern Hemisphere are a bit longer than in late December and soon plants will begin to respond to that change. And while we’re waiting for that, there are a few plants you might want to consider sowing right away for your summer garden.

Of course, don’t exaggerate: it is still far too early to start most seeds indoors. You won’t need to be thinking of sowing your tomatoes, peppers, petunias, etc. for 2 or 3 months yet. And let me warn beginning gardeners: starting seeds too early is far worse than being a bit late. If you follow this blog, I’ll let you know over the coming months when to sow all your favorite plants. For the moment, I only have two to suggest:



Cordyline australis

This popular container plant is variously called dracaena, cabbage palm and even spike or spike dracaena, but I stick to cordyline to avoid confusion. Its true botanical name is Cordyline australis, but seed catalogs have a long tradition of calling this plant C. indivisa which is, in fact, the name of a different species much more rarely grown. C. australis actually becomes a small tree in warmer climates (and when used indoors as a houseplant), but is usually grown as an annual, used for its spiky grass-like foliage as a centerpiece for container gardens.

This is an incredibly slow growing plant and you have to sow it very, very early for it to be the least bit presentable by spring. In fact, early January is on the verge of being too late. No special treatment is necessary: just sow it like any other “annual”, in moist soil, barely covering the seed… and wait oh so patiently.

Or wait until spring and buy a plant already started. If you’re the slightest bit impatient, buying a cordyline plant is the way to go!

For First Year Strawberries


Strawberries need an early start if you want to harvest them the first year.

If you want to sow strawberries (Fragaria x ananassa or F. x rosea) for a crop this spring, you’ll also have to get a move on. Of course, you can also wait until March and sow them in view of a harvest next year (like most perennial plants, the strawberry would not normally bloom in any abundance until its second year). But if you’re in a hurry…

Sow the seeds in a pot of moist potting mix, pressing them into the soil without covering them. Now seal the pot in a plastic bag and place it in the fridge, because strawberries need a cold treatment for good germination. After a month, remove the container from the refrigerator and expose it to light and heat: about 65 to 75˚F (16 to 24˚C). Germination is slow and can take up to a month.

When the seeds do germinate, it’s best to grow them under artificial lights (fluorescent or LED grow lights), at least until April. That’s because natural days are short when they first germinate and short days will slow growth down. With artificial lighting, you can offer 14-16 hours days and thus encourage plants to grow rapidly.

Place the seedlings about 3 to 4 inches (8 to 10 cm) below the lamp, raising it as the plants grow. Transplant them into individual pots when the third leaf appears. Finally, acclimate them to outdoor conditions early in the season and plant them out when temperatures are still cool, as this helps to stimulate bloom. Flowering and the first fruits will quickly follow.

Enjoy your first gardening activities of the New Year!

Laidback Gardener Tip of the Day


It’s Already Time to Start Sowing!

20150101Yes, I know, the New Year has just begun and it’s already time to sow the first seeds of the new season? It may not seem likely, but yes, if you want dracaena spikes (Cordyline australis, syn. C. indivisa) in time for your summer garden, you’ve got to start them really early.

What garden centers call “dracaena spikes” or just “spikes” are actually young plants of the New Zealand cabbage tree. They form a fountain-like plant with narrow arching leaves that has been used as the center plant (the “thriller”) in containers since Victorian times. But the growth of this plant – in fact a tree in its native land – is painfully slow, so you have to sow it very early in the season.

Soak the seeds in warm water for 24 hours (a thermos is handy for this purpose) and then sow them 1/2 inches (15 mm) deep in light soil. The seeds germinate very slowly – in 4 to 6 weeks – and need quite a bit of warmth: about 77- 80˚F (25-27˚C).

Personally, however, I no longer sow cabbage trees. Instead  I keep my plants from previous years by moving them indoors for the winter. You can even leave them outdoors in mild climates. USDA zone 9 is usually safe, sometimes even zone 8… until you get that one winter with a really hard, lasting frost, then you lose them. Indoors is safest everywhere outside of the Tropics.


A 5-year old Corydline australis with an obvious trunk. Within a year or two, you might want to consider cutting it down to a smaller size.

Obviously, over time, after 7 or 8 years or so, they become too tall and treelike for use as a container garden plant, losing their lower leaves and revealing a bare trunk you can no longer hide. When that happens, though, I take a cutting or air layer the top of the plant and that gives me a plant of just the right size for container use. Then I cut the remaining bare stem into segments about 3 inches (8 cm) long, which gives me a lot of cuttings I can pot up, plus a new plant will also grow from the stump. And you can even cut the thick roots into segments and they’ll sprout too. (If you do all the above, you’ll have to hold a cutting sale in the spring to get rid of all your new plants!) Again, though, you’ve got to take cuttings early if you want them to form usable plants by spring.

Of course, you could skip starting your own cabbage trees entirely and simply buy plants from a nursery in the spring. After all, they’re available just about everywhere. That’s fine if you have the money for that sort of thing, but I prefer to save my cash for plants I can’t get otherwise and instead keep my “spikes” from one year to the next.