Always Sow at the Right Depth

With seed-starting season in full swing, it’s worth pointing out that most seed packs indicate how deep you should sow the seeds they contain and how far apart you should space them. If they don’t, you will probably find this detail in a book or on the Internet.

If not, use the following rule which has served gardeners for generations: sow at a depth equal to 3 to 4 times the diameter of the seed and leave 1/2 inch (1,25 cm) between each seed (1 inch (5 cm) in the case of large seeds).

Do not cover very small seeds, however, those that are almost as fine as dust: their small size indicates that, in nature as in the garden, they prefer to germinate on the surface of the soil. Moreover, these same seeds usually need light to germinate, so when you start them indoors, always place their pots in a brightly lit location, even before they show any green growth.

Here’s how to sow fine seeds:

1. Sprinkle the seeds on the surface of a pot or tray of moist potting mix.
2. Gently press the soil with a block of wood so the seeds adhere to the soil, but aren’t covered.

3. Lightly spray with warm water: amessage to them it is time to germinate.

Here is a list of seeds it is best not to cover:

Agastache (Agastache foeniculum and others)
Ageratum (Ageratum houstonianum) Amsonia (Amsonia spp.)
Angelica (Angelica archangelica and others)
Angelonia (Angelonia angustifolia)
Annual gypsophila (Gypsophila muralis)
Astilbe (Astibe spp.)
Aubrieta (Aubrieta spp.) Balloon Flower (Platycodon grandiflorum)
Basil (Ocimum basilicum)
Basket of Gold (Aurinia saxatilis, syn. Alyssum saxatile)
Begonia (Begonia spp.)
Bells of Ireland (Moluccella laevis)
Bergenia (Bergenia cordifolia and others)
Bleeding Heart (Dicentra spectabilis)
Blue Fescue (Festuca ovina glauca and others)
Blue Poppy (Meconopsis betonicifolia and others)
Browallia (Browallia speciosa)
Canterbury Bells (Campanula medium)
Dusty Miller (Senecio cineraria, Centaurea cineraria and others) Clarkia (Clarkia unguiculata, syn. C. elegans)
Climbing Snapdragon (Asarina, Lophospermum and Maurandya) Columbine (Aquilegia spp.)
Corydalis (Corydalis spp.)
Cosmidium (Cosmidium burridgeanum)
Creeping Zinnia (Sanivitalia procumbens)
Dame’s Rocket (Hesperis matronalis)
Edging Lobelia (Lobelia erinus)
English Daisy (Bellis perennis)
Eucalyptus (Eucalyptus cinerea, E. globulus and others)
Everlasting (Xerochrysum bracteatum, syn. Helichrysum bracteatum)
Ferns (all species: Matteuccia, Athyrium, etc.)
Flowering Tobacco (Nicotiana alata, N. sylvestris and others)
Foamflower (Tiarella cordifolia)
Forget-Me-Not (Myosotis sylvatica and others)
Gaillardia (Gaillardia x grandiflora and others)
Garden Mum (Chrysanthemum x morifolium, syn. Dendranthema x grandiflorum)
Goat’s Beard (Aruncus dioicus and others)
Golden Marguerite (Anthemis tinctoria)
Hardy Gloxinia (Incarvillea delavayi and others) Heuchera (Heuchera spp.)
Himalayan Balsam (Impatiens glandulifera)
Ice Plant (Dorotheanthus bellidiformis and Mesembryanthemum crystallinum)
Kochia (Bassia scoparia, syn. Kochia scoparia)
Laurentia (Laurentia axillaris, syn. Isotoma axillaris)
Lemon Balm (Melissa officinalis)
Leopard’s Bane (Doronicum spp.)
Liatris (Liatris spicata and others)
Lungwort (Pulmonaria saccharata and others)
Masterwort (Astrance major and others)
Meadow-Rue (Thalictrum spp.)
Mealy Sage (Salvia farinacea)
Mexican Sunflower (Tithonia rotundifolia)
Mignonette (Reseda odorata)
Mimulus (Mimulus spp.)
Monk’s Hood (Aconitum spp.)
Mountain Sandwort (Arenaria montana)
Nemesia (Nemesia strumosa and others)
Oregano (Origanum vulgare) Oriental Poppy (Papaver orientale, P. bracteatum and others)
Osteospermum (Osteospermum spp., syn. Dimorphotheca spp.)
Ox-Eye (Buphthalmum salicifolium)
Penniseum (Pennisetum villosum, P. setaceum)
Perennial Candytuft (Iberis sempervirens and others)
Perennial Lobelia or Cardinal Flower (Lobelia cardinalis, L. siphilitica and others)
Rockcress (Arabis caucasica and others)
Rodgersia (Rodgersia aesculifolia and others)
Saxifrage (Saxifraga spp.)
Scarlet Sage (Salvia splendens)
Snapdragon (Antirrhinum majus)
Spanish Poppy (Papaver rupifragum)
Stock (Matthiola incana)
Summer Savory (Satureja hortensis)
Sweet Alyssum (Lobularia maritima)
Tansy (Tanacetum vulgare)
Throatwort (Trachelium caeruleum)
Thyme (Thymus vulgaris and others)
Virginia Stock (Malcomia maritima)
Wishbone flower (Torenia fournieri and others)
Yarrow (Achillea spp.)