Elisabeth C. Miller Library

Gardening Answers Knowledgebase

Search for gardening questions with researched answers, plus gardening tips, book reviews and recommended websites.

Browse the Knowledgebase


Recently Added Questions


It's late August, and some of my newly harvested Akane apples have a strange condition. From the outside they look normal, but when I cut into them, there are areas that look transparent and watery. They taste fine, but their appearance is kind of unappealing. What is causing this? Is there anything I can do to prevent it?


What you are describing sounds like a condition called water core, where the plant tissue has started to break down. According to Washington State University’s Tree Fruit Research and Extension Center there are many potential causes of the condition. Certain varieties are more susceptible than others. "Advanced maturity" (i.e., apples that have been on the tree a bit too long), and a lack of calcium may also be a factor. We have had a hot summer, and intense sunlight and heat may also have contributed. On the plus side, the watery areas tend to taste sweeter than the rest of the fruit, and people in some parts of the world (such as Japan ) actually seek out watercored apples for just this reason. The main problem is that affected fruit will not last long in storage. You may want to test your soil to detect any nutrient imbalances and then amend the soil accordingly.


Some of the cucumbers I am growing and harvesting taste just fine, but some are really bitter—I wonder if I should even be eating them. What causes this, and are they safe to eat (not that I want to)?


What you are describing actually has a name, toxic squash syndrome. It can affect plants in the Cucurbit family (so not only cucumbers but also zucchini, winter squash, and even melons). Oregon Health & Science University's fact sheet about this problem says that the cucurbitacins produced by plants in this family may have benefits for the plants themselves, warding off insects. But in humans, excessive cucurbitacin can cause digestive distress. Wild plants tend to have higher levels of this naturally occurring substance than varieties bred for human consumption. Still, environmental factors (such as uneven watering or fluctuations of heat and cold) can cause normally tasty cucurbits to turn bitter.

An article from North Carolina Cooperative Extension, "What Makes My Cucumbers Taste Bitter," says that cucurbitacin is mostly found in the leaves, stems, and roots of the plants but it can spread to the fruit as well. In your cucumbers, the highest concentration is likely to be in the skin and just below the surface of the skin. "Misshapen fruits are more likely to be bitter than well-shaped fruits. Some scientists even think that varying levels of fertilizers, plant spacing and irrigation frequency may also affect cucurbitacin levels. Bitterness seems to vary with the type of cucumber grown."

Because of the potential for unpleasant side effects, I suggest not eating the rest of a cucumber (or any other member of the Cucurbit family) if the taste is bitter.


Is it safe to eat pickles made from unripe walnuts (including hulls)? Are some types of unripe walnuts safe to eat and others not safe? I am not sure what kind of walnut is in my garden.

I am also a bit worried by articles I found online which say that juglone from walnuts can cause cell damage. Maybe I should skip this culinary adventure?


Pickled walnuts (from English walnut, Juglans regia) are a traditional British delicacy. The Royal Horticultural Society even mentions them. Alys Fowler's book, The Thrifty Forager (2011), says the walnuts for pickling must be picked in early summer before they harden. Traditionally, walnuts for pickling were harvested June 15, St. John's feast day. The famous 16th century herbalist John Gerard said, "the green and tender Nuts boyled in Sugar eaten as a Suckad, are a most pleasant and delectable meat, comfort the stomacke, and expell poison."

All walnut species have edible properties, though black walnut may be more bitter than English walnut. Edible East Bay published an article by Kristen Rasmussen in summer 2015 on pickling green walnuts from a native Californian species of walnut, Juglans californica.

Anyone who is sensitive to walnuts probably should avoid the pickled ones, too. Like many plants, walnuts have both edible uses and toxic properties. If you do not consume large quantities of walnuts (pickled or otherwise), I do not think there should be dire medical consequences. Toxic Plants of North America, 2nd ed., 2013 (Burrows and Tyrl) has a section on walnut (Juglans). The main toxicity concern discussed is that to horses, and in their case, it is mainly due to the use of walnut wood shavings in horse stalls.

A word about finding random articles on the internet: Context matters, and the citation you found about cell damage is in the context of using juglone (administered in a medical research facility) to kill cancer cells. It is not the context of everyday consumption of walnuts. Reliable sources are hard to find via the internet, and I would view with skepticism any site that is primarily commercial and does not cite trustworthy sources.

I could not find any references to the effects of pickling on the chemical composition of walnuts. Certainly, pickling (like any form of food preparation) will have some effects on nutrients. But since pickled walnuts are likely an occasional snack and not a staple upon which one's diet is founded, there is no cause for concern.


I saw some moss balls for sale in the gift shop of the new Nordic Museum. What type of moss is used? Is it native to Nordic countries? How do I care for one indoors?


The "moss" is actually a type of freshwater alga, Aegagropila linnaei, found in only a small number of northern hemisphere lakes. Other common names are lake ball or Cladophora ball. In Japan, they are called marimo (meaning a bouncy ball that is in water). The Ainu people of Hokkaido hold an annual Marimo Festival at Lake Akan to celebrate these charming lake goblins.

Iceland's Lake Mývatn once had the world's largest colony of lake balls but pollution has been altering the ecosystem there, and the mats of algae balls (colloquially called round sh*t or muck balls by the fishing community) began dying out. Their disappearance was first noted in 2013. There are some recent signs that the nutrient imbalance of the lake (caused by fertilizer runoff, and accumulation of bacteria) is correcting itself and that the ecosystem of the lake is bouncing back to better health.

To grow marimo inside, you will need a container that holds water, and a spot where the algae receive indirect sunlight. They prefer cool locations in nature, so they will do best if they do not get too hot (don't put them near a heat source, and if it gets hot in your home, you can cool them off in water in the refrigerator). To keep the balls floating, squeeze out some of the water from time to time. To propagate the algae, use scissors to divide the marimo in half after squeezing out some of the water (you can repeat this process and cut into fourths or eighths). Use thread to wrap the cut algae back into a rounded shape, tie the thread close to the ball, and put back into the water. Some people combine them with other plants and tiny shrimp in indoor aquascapes.


While hiking on San Juan Island, I saw these strangely beautiful, fluorescent orange clumps of hair-like substance (plant? fungus? something from outer space??) interwoven through the succulent-looking marsh plants. Can you tell me what this is?


That weaving (or strangling!) habit you describe calls dodder to mind, and there is a native coastal salt marsh dodder in that area called Cuscuta pacifica. Dodder is related to morning glories (the plant family Convolvulaceae). It is a rootless parasitic plant with nearly no chlorophyll and barely any leaves, and cannot photosynthesize on its own. It sustains itself by twining around other flowering plants and infiltrating their tissues with specialized branches on its stems, and coiling around them repeatedly as it grows. It may even be able to "smell" potential host plants.

Dodder can weaken its host plants, rendering them vulnerable to disease. However, there is some evidence that by thinning out the dominant host plants in a given area, it makes room for other species to take hold, increasing diversity.

The Washington State Noxious Weed Control Board lists a non-native species (Cuscuta approximata, smoothseed alfalfa dodder) as a Class C noxious weed, but it is not found in the area where you were. It is mainly a problem in agricultural land east of the Cascades. Dodder has various unfriendly nicknames in farming land: Devil’s Guts, Witches’ Shoelaces, Strangleweed, to list a few.