Cultivar Selection and Row Spacing: Science or Informed Opinion?
Over 100 years into commercial pecan production, we often still see more opinions regarding how to grow pecans than we see science. Even among pecan scientists, opinions vary considerably on many topics related to pecan production. The reason for this is that empirical data for some topics is so hard to come by in these long-lived perennial trees. It takes many years and a lot of land and resources to get reliable, replicated field data for mature trees regarding things like cultivars, row spacing, pruning, etc. If you add in the effect of environment throughout the wide range of conditions in which the pecan is grown, it adds a whole other level of complexity to consider.
Most of us prefer to rely on hard, scientific data but for some things, the data is simply not there at this time and we have to base decisions on informed opinions and each orchard situation will require a different set of factors to consider. There is no one perfect cultivar or row spacing for everyone to plant.
The design of a pecan orchard from cultivar selection to row orientation and spacing are often the most important factors to contemplate when planting an orchard. Once these factors are locked in and the planting is done, there’s no going back (at least not without considerable expense). These first decisions largely determine the management strategies you will have to employ in order for the orchard to be successful in the long term.
Cultivars have been discussed by myself and others ad nauseum so I won’t dwell on these in too much detail. Cultivar selection is more science-based than something like row spacing but, when making the decision, informed opinion will probably play a role here as well. When choosing a cultivar you have so many things to consider, but in the Southeast, your ability or willingness to do what it takes to manage scab is the most important determining factor regarding cultivar selection.
If you are in extreme South Georgia, or an area with lower elevation, or any area surrounded by woods, etc., you do not want to plant ‘Desirable’. With regard to established cultivars, a better option would be ‘Oconee’, ‘Sumner’, ‘Forkert’ or ‘Kiowa’ for export quality nuts. If you want to try a new variety, ‘Zinner’ or ‘Ellis’ would be my choices. Of the early harvest cultivars, I prefer the tried and true ‘Pawnee’. ‘Creek’ is a good choice for inter-planting if you are willing to fruit thin.
There are many that would disagree with the following statement, but if you are in the middle Georgia area, on high open land, and have the ability to spray fungicide as needed, I still believe ‘Desirable’ is hard to beat. Yes, you still have to spray for scab and yes we have issues to face regarding fungicide resistance, but no other variety to date has proven as profitable year in and year out as ‘Desirable’. It seems to have a market that is hard to saturate because they are so well known and they are in such demand due to their size, quality and consistency. Even its detractors have made a lot of money from ‘Desirable’. That’s not to say ‘Desirable’ is the only thing to plant in such areas, but if you are growing pecans commercially under the circumstances in which it can be grown, you almost have to have ‘Desirable’ as part of your operation.
I know I will face criticism from some for my next statement as well, but for Georgia, ‘Cape Fear’ can be profitable. I can’t speak for other areas and you have to be aware when you plant that there is a risk for bacterial leaf scorch but in truth, I have rarely seen it be enough of a problem in Georgia that I would not want to have a few ‘Cape Fear’. They are export quality nuts, they are easy to manage, they are excellent pollinators, and they produce a lot of pecans.
If you do not want to spray fungicide or you only want to spray it minimally, plant ‘Excel’, ‘McMillan’, ‘Lakota’ or ‘Gafford’ for medium to large-size nuts. ‘Kanza’, ‘Elliott’ or ‘Amling’ will be suitable for smaller nuts.
Row spacing is another important consideration that generates a lot of opinions. When we managed sunlight solely by tree removal in the Southeast, the decision was a little easier. With the development of hedging as a tool for managing sunlight, the choice of row spacing becomes more complicated.
Hedging looks very promising and I believe it is going to work in the Southeast. In fact, it may be the way we need to manage scab-susceptible cultivars in order to keep the trees at a size in which we can get good fungicide coverage. Still, hedging is not for everyone. Most growers will not want to spend the money for a hedging machine and custom hedging is usually at least $200/acre, not counting transportation fees. Once you start hedging, you need to be committed to maintaining the program.
Even with hedging, row spacing can get too tight. I believe that here in the Southeast, where sunlight is a limiting factor no matter how you manage it, a spacing of something like 25 feet by 25 feet is too tight. If you are going to hedge, I would go no tighter than 35 by 35, which is 35 trees per acre. I am not a fan of the old 40 by 40 spacing unless you are going to hedge. If you opt for tree removal over hedging with 40 by 40, you are left with a spacing that is either too wide or not wide enough at its final spacing. But I believe the original spacing with 27 trees per acre works with hedging.
If you definitely are not going to hedge, 30 feet by 60 feet would be okay but it is only 24 trees per acre and I would prefer a little higher tree density for better early production. As a sort of middle ground, my preference is 30 feet by 50 feet. At this spacing, you have 29 trees per acre and whether you hedge or remove trees to manage sunlight you should have adequate sunlight to maintain good production. My preference in the absence of hedging would be to thin this to 60 by 50 but stagger the tree removal so that if your rows run north and south, you still have 50 feet between rows but you have 100 feet to the east and west of the individual trees. The final spacing here would be 14.5 trees per acre. You could probably do the same thing with 30 X 45, which is 32 trees per acre at the original spacing and 16 trees per acre after the final thinning. In my opinion, both the 30 by 50 and 30 by 45 spacings would work well with hedging in the Southeast if left at the original spacing.
Well, as I mentioned at the beginning of the article, the pecan world is full of opinions. I’ve shared mine here, so let the speculation begin.