Ginseng Seed: What do we really know?
Part 2: Ginseng Seed Handling
May 15, 2013
Just over a year ago I posted Part 1 of this series, Seed Moisture. Since then, a lot has happened for all of us. One of the positive things is the completion of the second edition of my book, Growing Ginseng: A Beginner's Guide. Another positive thing for me was moving. While this move is good long-term for me, it caused issues with that seed bed where I planted the seeds I wrote about in the Part 1. If you recall, these were stratified seeds I took to the woods in fall 2011. Unfortunately, I had about five ounces left over in a plastic box that I put behind the seat of my pickup and forgot about them. They sat there all winter with the lid on the box. Obviously, this wasn't good for the seed as I explained in the first article. However, to my surprise, they started grinning when I added some water, so I planted them in a dedicated bed.
Here is the rest of the story. After I planted some of those grinning seeds, very few actually germinated and sent up sprouts. Most of them just lay there -some grinning and some not- in the bed just under the surface. Occasionally I tested a few of the seeds and they still seemed viable.
Fast forward to fall planting season 2012. About the middle of September, I had the opportunity to move to a better location and into a better long-term situation. This meant all the raised beds at the house had to move with me or be lost. Most of the SELECT rootlets were transplanted into the woods ahead of our move. The special bed with our dried out seed had to be moved also. I just skimmed a couple inches of soil from the top of the bed and put it in a plastic tote and took it with me. At the new location, I tilled up a spot for my cinnamon ferns and a few other things, and spread the seed bearing soil from the moved bed on top. I covered the whole thing with straw and waited.
Well, it's now the middle of May 2013. In addition to losing a fair amount of seed to the move, I have discovered an extensive network of vole tunnels under the straw of all my beds.
However, despite this, some of the seed that was left to dry out actually made it this spring. Below is the picture I took today.
As you can see, there are not a lot of them; however, it is evident that that horrible treatment didn't do as much damage as we would have thought it had.
So, with this in mind, let's recap what we've learned thus far.
1. We now know that ginseng seed can be kept much dryer than traditional wisdom has told us. In fact, it can be so dry that it will float, and still be completely viable. For this reason, let seed that appears overly dry to soak before float testing -maybe as much as overnight. One advantage to allowing seed to become relatively dry during stratification is that it will help reduce the favorable conditions for fungal disease while in stratification.
2. We now know that delayed germination isn't always because someone sold you green seed. The timer doesn't start ticking as soon as the ginseng berry falls from the plant. Ginseng seeds are considered to be morphological in dormancy. This means the seedling embryos are not fully developed after they fall from the plant. Ginseng also shares traits of morphophysiological dormancy, which suggests the seeds need a cold, warm, cold temperature sequence in order to break primary dormancy. Remember, they fall from the parent plant in the fall, go through the winter (cold), continue to mature during the summer (warm), and endure another winter (cold) before normally germinating in the spring when conditions become favorable. However, if the conditions are not favorable for the survival of the ginseng seedlings in the spring when they are expected, a second dormancy may be the result. In this case, germination could be delayed for up to two years according to some experts. For us, the most likely variables that will affect germination rates and dormancy are temperature and moisture. We need temperatures warming gradually for a full germination. We need about an inch of rain a week during the month of April and most of May to ensure good germination of stratified seed. If either of these are lacking, we may experience delayed germination though no fault of ours or our seed supplier.
3. Based on the type of dormancy ginseng displays, I no longer suggest my customers keep their seed in the refrigerator until they are ready to plant. Certainly you might and it will keep there most generally. However, if you are going to plant your seed before the ground temperature drops to the same temp as your refrigerator, you might be causing delayed germination in some of your seeds. I have come to recommend we learn from the commercial farmers and plant our ginseng earlier in the fall. If we plant by the end of August or anytime in September or most of October (providing Indian summer), there will be no shock for the seeds going from warm storage stratification boxes to the soil in which they will germinate the following spring. In my part of Ohio, the last half of September becomes a gamble against the fall rains as well, and getting seed planted at all at that point is iffy if you have a full schedule.
There are the high points aimed at getting the best possible germination when expected. However, what if we want to intentionally cause ginseng seed to delay germination? A commercial grower friend of mine conducted an experiment on just this issue. He harvested the seed as normal, stratified them with all the rest. But, in the spring when it came time to take the seed out of the cooler and put it into an open barn for warm summer storage before fall planting, he decided to keep one box of seed in the cooler an extra year. When the next spring rolled around, and it was time to take that year's seed out of the cooler, he moved the experimental box with them. They went to the open air barn like the rest, and in the fall were separated from the sand, bleached, and treated with a fungicide and planted like all the other seed from that current year's crop. The following spring, the germination rates were very consistent with the seed which had only been in stratification for one year as is normal.
This story tells us a couple things. First, ginseng seed is a might more resilient than we originally thought. Secondly, we know that the seed looks for warm, cold periods, but doesn't appear to care about the length of time of those periods. This also shows us that ginseng seed is fully capable of lying dormant for several years and still germinate when conditions become favorable.
So, at this point in time learning what we have, I have revised my recommendations for handling stratified ginseng seed when we receive it for planting in the fall. Here they are in a nutshell:
|1.||If your seed arrives in plastic bags, take them out unless you are going to plant them within a few days. If you leave them in the baggies, the seed cannot breathe and they often begin to mold after a few days. I've had very good luck holding seed in plastic totes. I can normally store up to 50 lbs per tote, but don't over fill the totes so I can mix the seed in them easily. Use a smaller tote or plastic shoebox size for smaller volumes of seed. I store them at room temperature -in a cool area like a basement is good, with the lids on. Every couple days I take the lids off, mix the seed with my hand to evenly distribute the moisture in the tote. I normally leave the lid off for a few hours after mixing, especially if there is excess moisture inside.|
|2.||Do not add water to your seed. As we have seen, ginseng seed can do very well when it appears very dry. Adding water is inviting disease issues. We have enough trouble with disease as it is without creating conditions favorable for its appearance. The best recommendation is to plant your seed as soon as you can after you receive it from your dealer.|
|3.||Do not refrigerate stratified seed. The only exception would be if you must wait until the ground temperature is near the temperature of your refrigerator, or want to plant in the spring. I highly discourage spring planting. I have seen only minimal results at best. Some folks have a knack for it, but most don't. There has been some evidence that refrigerating stratified seed may contribute to delayed germination.|
|4.||Avoid bleaching stratified seed. Unless you have reason to believe that your seed has been exposed to fungal organisms since you received it. When seed comes out of the stratification boxes of a commercial operation, they bleach it then. There is no benefit to bleaching it a second time, and I have seen some evidence of bleach killing seedlings. I am cautious that it might do the same to stratified seed if left on too long or not washed off completely. Additionally, this adds additional unneeded water.|
|5.||If you are going to treat your seed, do it right away. If you plan to treat the seed with a fungicide prior to planting, do it soon after you receive your seed from your supplier. As of the release of my book, there were four approved seed treatment fungicides of which I was aware. These are Apron (Mefenoxam S-isomer), Maxim (Fludioxonil), Rancona (Ipconazole), and Sebring (Metalaxyl). It doesn't make sense -if you are going to treat the seed before planting- that you wait until the day of planting to do so. By treating your seed early, you may avoid inoculation of seed if they are contacted by some disease organism prior to their treatment. I've been rather open about my willingness to use chemical fungicides to keep my ginseng alive in its early years. Therefore, I have no problem recommending my customers treat their seed before planting. In fact, I have learned from the commercial growers, and not only treat the seed prior to planting, but also spray the beds before laying mulch. I have had excellent results with this method.|
Ultimately, the goal is to have an on time, high percentage, even germination of the seed we plant. I am convinced the best way to do this is by handling your seed properly after you receive it. If you receive poor seed, you will get poor results regardless of your handling. However, keep in mind, if you receive top quality seed and handle it poorly, you will get poor results also. But, if you receive high quality seed from a reputable dealer, and handle them correctly, a germination as high as 80% or more is not at all unreasonable.
This picture of one of my SELECT seedling beds was taken the middle of May. There are a few seedlings still showing up, but not many. I plant very thickly in these raised beds to conserve space, spray, and time. Under normal conditions we would never like to plant this heavily. However, it gives a good indication of what germination rates can be had with proper seed handling and cooperative Mother Nature.