To Parsnip or Not to Parsnip

When I came up with the original plan for the vegetable garden, I was focused on relatively simple things to grow (since I have no idea what I am doing) and things which we would use.  Somewhat unusual among the chosen plants were parsnips.  However, I had stumbled upon a roasted veggie recipe at Thanksgiving time last year.
 

Recipe from 11-18-15 Dallas Morning News

It was easy to fix and was really good.  The only major challenge was finding the parsnips.  Tom Thumb did not seem to have them, at least when I first fixed this recipe.  I found them at Whole Foods, but knew they were unusual when the checkout clerk at Whole Foods was stumped and had to ask me what they were.


Based on that experience, I thought they might be a good candidate for growing in our garden.  Of course, I did the appropriate Google search before making a final decision.  Multiple sites indicated they are easy to grow as long as fresh seeds are used.  I even found someone in Denton that had had success.  They take a VERY long time to mature, 95-105 days according to the seed packet I have-but could be 50 or 60 days longer for some varieties.

Planting of parsnips in Texas is in fall with harvest in March.  That is important for the total length of time, the cooler weather in general, and finally the need for some really cold weather (frost or freeze) that causes some of the starches to change to sugar, producing the sweet nutty flavor. 

Although I did not see mention of this on the other growing sites, I did note the following disclaimer on the blog post from the grower in Denton:

Warning: The leaves and stems of parsnips contain a juice that can cause Phytophotodermatitis in some people. Phytophotodermatitis happens when the sun interacts with the juice on the skin causing a reaction that resembles sunburn spots. These spots can also develop blisters. This is much less of a concern for garden parsnips compared to wild parsnips, but just to be cautious I wear rubber gloves while harvesting parsnips and do not wipe my face or eyes during the process.

I did not think a lot about that other than to plan for gloves and long sleeves when working with the leaves.  How bad could it be?  I routinely survive poison ivy outbreaks after hiking in the woods.

Yesterday I stumbled across this post on Facebook about a woman in Iowa and her run in with wild parsnip that required a trip to the emergency room.  Admittedly this was "wild" parsnip, but I thought I would do some more investigation.  Googling "burns from parsnip" produces hundreds of hits.  Hmmmm...I might need to look into this some more.

The best discussion I found about what actually happens was this article in the North Woodlands magazine.  Although many different plants besides parsnips (e.g. poison ivy, poison oak, nettles) have developed chemical defense mechanisms, parsnip poison and the phytophotodermatitis that it causes is fundamentally different from poison ivy:

The toxin in parsnip sap is different from the toxin found in poison ivy or poison sumac; the reaction your body has to it has nothing to do with your immune system, and everyone is susceptible. The harmful chemical compounds – specifically, psoralen and its derivatives – are photosensitizing, which means they’re activated by ultraviolet radiation from the sun. (Smear yourself with parsnip sap in a dark closet, and nothing will happen.)

When you get some sap on your skin, the sap absorbs solar energy, then releases it in the form of heat. On a micro level, the psoralen molecule lodges between two strands of DNA, and sunlight fuses the strands together. “You can imagine what this does to an insect that tries to eat the plant,” says Vogelmann.

The chemical reaction damages skin cells and feels very much like a burn. This is a key difference between the phototoxic dermatitis caused by poison parsnip and the allergic contact dermatitis you get from poison ivy. Parsnip burns feel like burns, whereas poison ivy rashes are often more itchy and irritating than painful.

While the pain from a parsnip burn is relatively short-lived, an encounter can leave long-lasting scars. As part of the recovery process, the body produces dark pigmentation that is thought to serve as a protective mechanism against further UV injury (sort of a super-suntan). These dark splotches can linger on the body for years. In an interesting twist, people with psoriasis and similar skin-pigment disorders sometimes turn the toxin to their advantage and use psoralens to help increase their skin’s sensitivity to ultraviolet light.

A variety of plants in the carrot family (parsnip, parsley, celery, hogweed, carrot, and wild carrot) can cause phytophotodermatitis.  Some of these are not much of a problem, but some can be quite serious.  The worst is giant hogweed, which can grow up to 14 feet tall and is very dangerous, causing severe phytophotodermatitis and even blindness due to its large amount of sap.  Fortunately giant hogweed does not grow in Texas!

So what does all of this have to do with parsnip in the garden and is it dangerous?  Apparently some field workers picking domestic parsnip and even produce workers in grocery stores have developed phytophotodermatitis from domestic parsnip greens.  Yes, it can leave lasting scars.  Could I work around the problems?  Yes, I am sure I could.  It is far less dangerous than many of the things I dealt with in the lab.  However, I am not sure it is worth it this first year when so many other things are new.  There are also additional hazards of working with such a plant in the crowded environment of a square foot garden.  I think I will pass this year.  I am only out the $1.69 for the packet of seeds.  Maybe in another year or two, when I know more about what to expect, I will give parsnips a try.