The first question asked by anyone interested in growing fraises des bois is “what yield can I expect”? Of course, the second question is how much can I charge my customer. We are going to deal here with the first question, yield or productivity.
This question might seem to be simple and have a simple answer but it is anything but simple. So many factors have to be considered such as:
- plant age
- plant density
- culture (open field vs protected environment or even hydroponic)
- and more
I even had a customer ask how many plants he would need to grow to produce 50 pints of fruit per week. You can be assured that I didn’t stick my neck out on that one.
When I started growing fraises des bois years ago I only had information from books and magazines to go on. This was long before the internet. Most garden writers at that time and even today are not very encouraging about the yield that one can expect from fraises des bois. Most consider them dainty little ornamental plants whose place is planted 6″ apart along a sidewalk. Grown this way they will be as unproductive as the garden writers predict.
With nothing to go on expect years of experience growing the plants I set out in 2008 to get some hard data on productivity. I chose 2 year old plants from several cultivars and tried to optimize the growing conditions. The beds where the plants were planted were built up with compost and supplemented with fertilizers. Plants were irrigated as needed to keep the soil moist. Protection was provided to reduce damage from winds and rains. Pesticides were applied as needed to reduce loss from any possible pest.
The results were amazing to even me. The top two producing cultivars were ‘Yellow Wonder’ and ‘Alexandria’. This was before we acquired cultivars like ‘Reine des Vallees’ and ‘Bowlenzauber’ (two cultivars we consider superior to ‘Yellow Wonder’ and ‘Alexandria’). We followed production for an entire spring from first fruit until the fruit were tiny in the summer and not worth harvesting. We harvested fruit and graded it on the spot and weighed it per plant. The results were analized statistically. These top two cultivars produced 0.9 lb of fruit per plant which consisted of over 700 berries per plant. They were statistically equivalent.
We did it backwards, but the following year we did a similar study but with plants in their first year of productions. There were differences in the top cultivars and the amount of fruit was about half of what we got from two year old plants.
Our literature searches finally started finding information on fraises des bois productivity. A Japanese study around the same time as our study had similar results for one year old plants but did not follow them into the second year.
We intend to expand this whole page with the exact numbers and possibly with charts and graphs but in the interest of getting as much information online as possible we will provide summaries only at this time.
It is worth mentioning that for years we did not consider hydroponic production of fraises des bois to be practical. Afterall, hydroponic systems like NFT usually use small blocks of media. Alpine strawberries produce a clump and the larger the clump the more productive. We believed that limiting the size of the clump with the hydroponic media would limit production.
Since then, we have found results of several studies done in Europe, primarily in Sicily where hydroponic NFT systems yielded 200 to 300 grams of fruit per plant. This is the range of yields we found for our best producers in year one using traditional field culture. We even found a study in the literature (Sicily again) where plants were followed for a full year, spring and winter producing periods. The total yield for the year was over 1800 grams per square meter. We are still digging into the specifics of this study to learn the details of the production system. It seems that a language gap has resulted in reason to look further into the details. Still, that level of production is phenomenal and should make garden writers reconsider their original positions on productivity of fraises des bois.
So, let’s get back to that bulleted list that we started out with. Plant age is definitely a factor in yield. One must consider the cost of maintaining plants for several years and ask whether the additional production is worth the cost.
Cultivar also plays a major role in productivity. There are those that say all red fruiting alpine strawberries are the same. They wouldn’t say that if they saw the results that are obtained when cultivars are tested side by side by not only me but researchers around the world. Many of the studies are done with ‘Reine des Vallees’ (= ‘Regina delle Valli’). The reason is that this is the commercial standard in Europe. It is the standard for a reason, it is productive.
Climate is also a major factor. I know growers in coastal areas of California who are producing fraises des bois year round. Their climate is perfect for this crop. Growers in less favorable climates are turning to protected environments to grow this crop. Some are using supplemental light and heated spaces to compensate for a climate not as favorable to the crop. All of these inputs must be assessed and the ROI must be calculated. A high value crop like this makes it more feasible to pay for these inputs.
Plant density is an important consideration, expecially for protected culture. Many growers and even some researchers looked at vertical growing, that is, growing multiple layers of the crop. Lower levels suffer from low light which results in less yield per given area. Very little has been done worldwide to consider this factor. Of course, here in the U.S., nothing has been done.
Plant culture such as protected environments is another major factor in yield, especially marketable yield. A high value crop like this depends on the highest quality product. To attain that quality level in most climates it is necessary to protect the crop. One seeming exception is in Spain. Arzagot has been producing quality fraises des bois (they call them woodland strawberries) for a number of years. They grow in the open field and start from seed every year. Here is a screenshot of their site:
Arzagot is one of the major exporters in Spain with a good deal of their production coming to the U.S. Their site is especially interesting because they give information on the amount of time it takes to pick a kilo of fruit and the number of berries that make up that amount of fruit. We use this example about plant culture and climate but it will be used in other discussions about this crop.
I will note that references will be added soon about the studies that have been done with hydroponics. I find this a potentially rewarding growing method that will maximize production because of the method itself but also because the plants will be grown in a protected environment where all factors are optimized. The crop can reach it’s true potential and reap the highest rewards in quality, yield and of course price and ROI.
Because of the importance of the yield factor we will likely split up the discussion to multiple pages. There are methods being used to grow this crop that were not even mentioned. We are aware of growers using hanging baskets to grow the crop. Tabletop systems are used to produce strawberries in Europe and fraises des bois can be grown this way. We are not sure if it is a method being used but it is worth mentioning in a comprehensive discussion. This section is particular will be fine tuned and expanded as needed. So, come back from time to time to this discussion to see what has been added.