Lunar gardening

I’ve heard that planting the garden according to phases of the moon has some benefits, but I’ve always wondered if there’s any truth to this. Is there any research out there on this topic?

Thank you for your interesting question. I found comments from the point of view of an astronomer on Cornell University’s “Curious About Astronomy?” webpage, excerpted here:

“There are two main ideas behind moon gardening practices. First, lunar gardeners believe the moon’s gravitational pull affects the flow of moisture in the soil. Just as the moon has a noticeable effect on the oceans in the tides, the moon may have a subtler effect on smaller bodies of water and thus change the levels of water in the soil. For example, to take advantage of the lunar cycle, a gardener would avoid turning over the soil in his or her garden when there is the most moisture in it (and thus when the soil was hardest to turn over) which lunar gardeners propose is during the new and full moons. Another, less direct, proposed connection between the moon and gardening is that moonlight is thought to have an effect on seed germination because exposure to light can enhance germination.

“I could not find any extensive scientific studies conducted to test the proposed benefits of lunar gardening. There was a study done by the Agricultural Research Service in Iowa where they found a link between weed germination and exposure to light. They determined that tilling the soil (i.e. bringing weeds to the surface) was best done at night by a new moon (when there was as little light as possible). Tilling in the dark led to less weed seed germination and thus to fewer weeds in the garden.

“More studies definitely need to be done to test the possible connections between the Moon and gardening before I am convinced. However, I would bet that with the extra care and attention lunar gardeners give their gardens, the gardens benefit whether the success is due to the Moon or not.”

For more information on the ideas behind lunar gardening check out Caren Catterall’s site, Gardening by the Moon.

Here is another interpretation, from an individual who tested to see if moon planting made any difference in the success of crops, from Undeceiving Ourselves:

“Gardening folklore in general is often based on accurate observation. It’s just that the reasoning may be faulty. For example, over the years I’ve tested various bits of ‘companion planting’ folklore. And some actually work, but not because ‘basil likes tomatoes’ (which actually doesn’t work because basil planted near tomatoes tends to get black spot, while the tomatoes do neither better nor worse). Never trust a gardening book that tells you that marigolds deter aphids–beans, onions and fuchsias planted with marigolds get more aphids, not fewer, and I suspect the same is true of other plants. On the other hand, root knot nematodes do appear to avoid the root secretions of marigolds, though a companion crop of marigolds can make the problem worse for other reasons. So remember that a gardening observation (like Moon planting) may be true even though the reasoning is faulty.”

There are journal articles which discuss lunar gardening. Here are a few:

Weird or wonderful? (organic farming) by Paul Kingsnorth in The Ecologist, February 2008. Abstract: Different kinds of gardening techniques have come up like planting according to the phases of the moon that promises higher yields and better flavors. There is also biodynamic growing that claims to be founded on a holistic and spiritual understanding of nature.
La lune et la nature vivante (The moon and living nature) by Lucien Baillaud in Revue des Sciences Naturelles d’Auvergne, 2003. Abstract: Popular traditions regard the effect of the moon on plants. Patented researchers strive to track
lunar influences without a known functional rule: many people of the sciences disagree with their results. These questions present themselves in very diverse manners to those who observe nature, to those who cultivate their gardens, or to those who try to reason.
Fractured Physics by Lynne Johnson in The Physics Teacher, Vol. 32, May 1994
Lunar Gardening: common sense or lunacy? by Kat Neely Jones in GreenPrints, Summer 2007
Lunar-Sidereal Rhythms in Crop Yield: A Review by Nicholas Kollerstrom and Gerhard Staudenmaier in Biological Agriculture and Horticulture, 2001, Vol. 19, pages 247-259. Online version.

The book The Old Farmer’s Almanac Book of Garden Wisdom by Cynthia Van Hazinga (Random House, 1996) also has a brief discussion of gardening by the phases of the moon, and mentions it as a principle of biodynamic gardening. The following information on biodynamic gardening comes from National Sustainable Agriculture Information Service’s resources (no longer available online), excerpted here:

“Planetary Influences

“Lunar and astrological cycles play a key role in the timing of biodynamic practices, such as the making of BD preparations and when to plant and cultivate. Recognition of celestial influences on plant growth are part of the biodynamic awareness that subtle energy forces affect biological systems. A selection of resources are listed below. On examination of the variations in agricultural calendars that have sprung from the biodynamic experience, it is apparent that differing viewpoints exist on which lunar, planetary, and stellar influences should be followed.

“Stella Natura – The Kimberton Hills Biodynamic Agricultural Calendar (…) is the biodynamic calendar edited by Sherry Wildfeur and the most prominently known calendar of this type in the United States. It contains informative articles interspersed with daily and monthly astrological details, and lists suggested times for planting root, leaf, flowering, and fruiting crops.

“Working with the Stars: A Bio-Dynamic Sowing and Planting Calendar (…) is the biodynamic calendar based on Maria Thun’s research and is more prominently used in Europe. Of the three calendars mentioned here, Thun’s calendar relies more heavily on planetary and stellar influences. It contains research briefs as well as daily and monthly astrological details, again with suggested planting times.

“Astronomical Gardening Guide, available through Agri-Synthesis in Napa, California for a self-addressed stamped envelope, is the biodynamic gardening guide compiled by Greg Willis of Agri-Synthesis. This calendar, which is a simple 2-sheet information leaflet, focuses on lunar phases.”

Lunar gardening, Planting time

Training goji berry vines

I am growing goji berry plants in my garden. I was hoping their growth habit would be more upright but they are sprawling wildly. Do you have suggestions for training them? Should I be concerned that they might become invasive?

Susanna Lyle’s book Fruit & Nuts (Timber Press, 2006) says these shrubby vines are short-lived, peaking in berry production at about 5 years of age and typically living for 8 years or so. She advises planting them near a fence or trellis so that they can be trained up it; some sprawling is to be expected. Utah State University Extension’s October 2015 article, “Goji in the Garden,” offers general cultural information (while mentioning that the plant is a weed in some areas).

Lycium barbarum (goji, also called wolfberry and boxthorn) can be invasive (or at least aggressive) in some areas. An article by Vern Nelson in The Oregonian (August 17, 2008) mentions this tendency, and suggests containing them in a 4 by 5-foot square support structure. Be aware that “wolfberries take root wherever they touch the ground.” This is worth bearing in mind, as is the fact that Lyle’s book says “the extensive root system can help stabilize banks,” which one could interpret to mean that removing unwanted plants might be a fair bit of work!

Suckering roots are only one way the plant spreads; seeds are another. Goji berry (boxthorn) is the “Plant of the Month” in the Whatcom County Master Gardeners Weeder’s Digest from August 2006. Author Cheryll Greenwood Kinsley notes that when the plant was first introduced in Europe, people weren’t enamored of the fruit but birds were, and now “the shrub has naturalized in Britain and is listed as a noxious weed on two continents and in at least some parts of several states, including Montana and Wyoming.” She recommends keeping the birds away from it to discourage its spread.

Invasive plants, Lycium barbarum, Training plants

Distinguishing Hydrangea petiolaris from Schizophragma hydrangeoides

There’s a climbing vine in my garden which has hydrangea-like flowers. I have lost the tag, and don’t know if it is Hydrangea petiolaris, or Schizophragma hydrangeoides–how can I distinguish one from the other?

There is an article in Arnoldia (the journal of the Arnold Arboretum at Harvard University) from July 24, 1933 which explains that the two plants are related, but the flower ‘petals’ (which are actually sepals) surrounding the center are distinct:
“In Hydrangea petiolaris this encircling tiara is composed of greenish white flowers, each one made up of four rounded sepals. In Schizophragma hydrangeoides these showy sepals are a purer white and they are borne singly rather than in fours.”

University of Arkansas Extension also says that Schizophragma “differs in flowering time (after climbing Hydrangea) and in the fact that it protrudes less from structures.”

There is another less commonly grown climbing Hydrangea, Hydrangea integrifolia, an evergreen that grows to 40 feet tall and 20 feet wide. Its flower buds look almost like those of peonies, and its leaves are elongated and glossy.

Hydrangea, Schizophragma hydrangeoides

Controlling Parsley-piert

Slowly but surely, what’s left of my untended lawn is being overtaken by a small weed with fan-shaped leaves. It reminds me of a tiny Lady’s Mantle. What is it, and is there any hope of getting rid of it without herbicide?

Your description sounds like Aphanes australis, whose common name is slender parsley-piert. The common name derives from the plant’s leaves which resemble parsley, and the French ‘perce-pierre,’ meaning ‘break (or pierce) stone.’ It thrives in dry, exposed, or barren soils. North Carolina State University’s Turf Center describes cultural control methods:
“Winter annual broadleaf weeds germinate in the fall or winter and grow during any warm weather, which may occur in the winter, but otherwise remain somewhat dormant during the winter. They resume growth and produce seed in the spring and die as temperatures increase in late spring and early summer. They quickly invade thin turf areas especially where there is good soil moisture. Shade may also encourage growth. Many have a prostrate growth habit and are not affected by mowing. A dense, vigorous turf is the best way to reduce the encroachment of winter annual weeds. First, select adapted turfgrass cultivars for your area and then properly fertilize, mow, and water to encourage dense growth.”

It sounds like lawn renovation might be a good idea. If the parsley-piert has intense competition from a happily growing lawn, it will not thrive. Seattle Public Utilities has good resources on lawn care.

Aphanes australis, Lawns–Care and maintenance, Weeds

Tomatoes and blossom-end rot

It’s summer and my husband wants to add lime to our soil because some of our tomatoes have blossom-end rot. He thinks this will correct the problem. I think we would do better to make sure our tomatoes aren’t drying out, and then work in soil amendments next time around. Also, couldn’t we use eggshells for calcium instead of lime? We have a ready supply from our backyard chickens!

I think you are on the right track. Blossom End Rot (BER) is a physiological disorder that tends to affect larger tomatoes rather than smaller ones. According to Craig LeHoullier’s book Epic Tomatoes (Storey Publishing, 2015), some varieties are especially susceptible: “Roma/paste varieties, and some of the longer indeterminate sauce types like Opalka and Speckled Roman. Adverse growing conditions [such as drought stress or low calcium levels] can make it problematic for many other varieties as well.”

All print and web sources I consulted mention environmental conditions as a cause of this problem. It starts through the supply of water and calcium in the developing fruits. The effects may be seen on plants exposed to a period of drought during rapid growth; root damage; heavy, wet, or cold soil; excess salt in the soil.

A soil test is the ideal starting point to make sure the pH is adequate for tomatoes. Epic Tomatoes recommends amending the soil with lime if necessary. (Washington State University Extension says the time to do this is 2-4 months before planting, not in the middle of summer!) Mulch around the base of the plants to conserve soil moisture during hot spells and water regularly. Another reason a soil test is a good idea is mentioned by British Columbia author Linda Gilkeson in her book Backyard Bounty (New Society Publishers, 2011):

“Your soil might have enough calcium, but it isn’t available, or the plant can’t take it up fast enough. This is often because the movement of calcium inside the plant has been inhibited by drought stress, possibly from irregular watering. This is often seen on tomatoes in containers that experience alternating dry and wet soil. It can also be caused when plants grow too fast as a result of too much nitrogen fertilizer.”

Since you prefer not to use lime (the dry powdery texture of calcium carbonate can be irritating to the skin and eyes), you will be pleased to know that the use of eggshells is mentioned by Mike McGrath in You Bet Your Tomatoes! (Rodale Press, 2002). At planting time you can “put some crushed-up eggshells into the planting hole.” Make sure the eggshells are ground to a fine consistency.

Don’t forget that those damaged tomatoes can still be used–just cut off the bad parts!

Plant-water relationships, Soil amendments, Tomatoes–Diseases and pests

On the difference between sweet potatoes and yams

What is the difference between yams and sweet potatoes?

According to Elizabeth Schneider’s Vegetables from Amaranth to Zucchini (William Morrow, 2001), the orange vegetable that many of us commonly call a yam is in actuality a type of sweet potato (Ipomoea batatas). So is the ivory-fleshed version (also known as Korean, Oriental, or Japanese sweet potato), and so is the boniato-type (a larger sweet potato with fragrant flesh that bakes up dry and fluffy). All sweet potatoes originated in the New World, though many are now grown and used back in Europe and Asia as well.

The true yam has many varieties, all of which originate in the Old World, but which may also be grown and sold here now, particularly in specialty markets. All of the true yams belong to the species Dioscorea, which has 60 edible species (10 of them widely grown). Few of them are sweet; none are as sweet as the orange vegetable we picture with marshmallows at family feasts in the US. Here is a sampling of some true yam types:

White yam (Dioscorea alata), ñame blanco –“sweet, delicate, mild”
Purple yam (also Dioscorea alata), ube, ratala, or kand — “gently sweet, with a touch of smokiness, meatiness, and nuttiness”
Cushcush yam (Dioscorea trifida), mapuey, yampi, or igname couche-couche — “dry, fluffy, and starchy”
African white yam (Dioscorea rotundata), Guinea yam, Ghana yam, fufu yam — “5 pounds” “potato-like”
Chinese yam (Dioscorea esculenta), lesser yam, ñame papa “like a fibrous russet”

The following link may also be of interest. Library of Congress explains the confusion between these two types of tubers.

Botanical nomenclature, Dioscorea, Ipomoea batatas

Strawberry cross-pollination and varieties to plant in Seattle

I have organic Rainier strawberries in a raised bed. I’d like to plant organic everbearing strawberries in the same bed. Is there a problem with cross-pollination? What would be your recommendation for the best strawberry varieties to plant in Seattle?

Strawberries can reproduce by runners or by seed. Those which are reproduced by runners will be clones of the parent plant, but those which grow from seed may cross-pollinate.

Here is more information from the Royal Horticultural Society.

Excerpt:
“Strawberries can be propagated in late summer, but no later than early autumn, by sinking 9cm (3.5in) pots filled with potting media, such as general-purpose potting compost, into the beds and inserting individual runners into them. Sever the new young plants from the parent plant when rooted. Perpetual strawberries produce few runners and new plants are best bought in annually.
“Seed-raised cultivars are available but are not recommended*, except for alpine strawberries.”
*I suspect this is because you can’t know what the resulting new generation of strawberries will be like–tasty or not so tasty.

So I think as long as you harvest your fruit, and don’t let fruit ripen and drop into the bed, you can allow runners to produce new plants and they should be the same varieties as their parents. That being said, it’s usually good to replace strawberry plants after a few years, just to keep disease problems down (the RHS link above says to replace every 3 years or so).

I’ve had good luck with Shuksan (June-bearing), and I think I may have grown Tristar (ever-bearing) before, too. Oregon State University Extension has a guide entitled “Strawberry Cultivars for Western Oregon
and Washington” which recommends these varieties and several others..

There are many more varieties listed in the Sunset Western Garden Book of Edibles (2010). If you are looking for sources, you might try your favorite local nurseries, but also mail order nurseries like Raintree, Cloud Mountain Farm, and Burnt Ridge. The Northwest Flower and Garden Show in February often has vendors selling strawberry plants.

Cross-pollination, Fragaria, Propagation

Lightning and soil fertilization

We had quite a lightning storm today, and it made me think of something a friend had told me. He used to farm in Eastern Washington, and he said that lightning was good for the soil and the crops. Is this pure folklore or does it have some scientific basis?

This isn’t just folklore. According to the Indiana Public Media’s Moment of Science, “there is enough electrical energy in lightning to separate the nitrogen atoms in the air. Once the atoms are separated they can fall to earth with rain water, and combine with minerals in the soil to form nitrates, a type of fertilizer.”

Effect of storms, Soils

blooming dogwood

I have a 22-year-old Eddie’s White Wonder Dogwood. It bloomed the first three springs after planting and then stopped blooming until this spring.

It is planted at the edge of a woodland, facing south. It received summer water the first few years, but not since then, because Sunset Western Garden Book advised re: Cornus nuttallii, part of Eddie’s cross: “Give infrequent summer water.”

I did water it more last summer, as it was so hot and dry in our area. And it finally bloomed!

My question–Do you think that the bloom this spring was the result of more water during the summer, or did the tree have to reach a certain age to start blooming each spring?

There are several reasons that Dogwoods fail to flower. Flowering dogwood does need regular water, according to Sunset’s 2001 edition. Other possibilities might be the age of the tree, and extreme temperatures, such as cold, which may kill the buds.

I would suggest continuing to water and see if it flowers again next season.

There is some discussion about dogwoods failing to flower on the forum of University of British Columbia Botanical Garden. Possible reasons include the age of the tree (not applicable in your case), excessive use of fertilizer, cold damage to buds, lack of sun, and more.

The book 1000 Gardening Questions & Answers (The New York Times) has a section entitled, “Why Won’t It Bloom.” Reasons that dogwood may not flower are similar to those described above:

Cornus, Cornus florida, Cornus nuttallii

Growing grapes in Seattle

What grapes for eating ripen in the Seattle area? I do grow concord, but are there any red or green grapes that ripen in this climate?

Both WSU and OSU Fruit Research Stations recommend Buffalo, Canadice, Van Buren, Vanessa, and Venus.

Following is WSU’s entire list:

Table grape varieties (*currently planted at Mount Vernon)
Buffalo – midseason Concord type, blue
Canadice* – early pinkish red
Interlaken Seedless* – early white, vigorous
Lynden Blue – very early blue, seeded
Mars* – medium early, blue
Reliance*- early, red, table and juice
Saturn* – medium early, red
Van Buren – blue Concord type, early
Vanessa* – early red
Venus* – early red
NY 78.836.06* – selection from Geneva, NY breeding program

(Source: Washington State University, Mount Vernon)

You may find Oregon State University’s publication about Growing Table Grapes by Bernadine C. Strik of interest as well.

Vitis