by Amanda Green, Tree Fruit Specialist and Kathryn Carter, Fruit Specialist, OMAFRA
This spring has been frustratingly wet. According to Agriculture Agri-Food Climate Agroclimate maps, over the last 30 days, most tree fruit growing areas have received greater than 200% of normal precipitation. Some of the “drier” areas have received 150-200% of normal precipitation. Growers who are on heavier soil are probably delayed in planting. Here are some tips for maintaining your trees in cold storage and your later planted trees.
Maintaining trees in cold storage
- Keep trees dormant by storing in a cooler. Make sure that the cooler is not used for apple storage as the ethylene from the stored apples will induce the trees to come out of dormancy.
- For longer term storage of more than a few days, take trees out of shipping plastic. Place the trees upright in bins and cover roots with moist woodchips, sawdust, peat or sand. Check trees regularly to make sure that the material around the roots is kept moist.
- If you don’t have cold storage or cold storage that has not been used for storing apples, communicate with your nursery to delay delivery of trees.
- If you already have the trees delivered and don’t have cold storage you can keep the trees in a cool spot out of the sun for a few days. If you are delayed from planting for more than a few days, you can “heel-in” the trees to keep the roots from drying out but buds will break dormancy. You can “heel-in” trees by digging a V-shaped trench, deep enough to cover the roots. Put a layer of mulch (wood chips, sawdust or peat), sand or sandy soil in the trench first. Lay the trees in the trench with the roots against the steeper side and cover with mulch, sand or sandy soil (Figure 1).
Development of young trees when planted in cool wet conditions
- Most fruit trees don’t like “wet feet” and young trees that have already been planted are enduring cool wet conditions.
- Waterlogged soils limit root/tree growth and reduce mineral absorption, resulting in leaves turning yellow and remaining small. Once temperatures warm up and the soils dry out, the young trees often recover.
- Prolonged waterlogging will eventually result in root death. Often, fruit trees in poorly drained areas are infected by Phytophthora root and crown rot, slowly declining over one or more years. For additional info on these diseases please refer to Ontario Crop IPM.
- For apple trees, rootstocks that don’t preform as well on poorly drained soils are M.9, M.26 or MM.106
The importance of site selection and having good drainage
- With climate change and more extreme weather (including extreme rain events), good drainage in orchards will be important in ensuring a healthy productive orchard.
- Orchard drainage helps improve the health of the trees resulting in better tree growth, yields and healthier trees. Effective orchard drainage also mitigates wheel rutting that contributes to slips, trips and falls of orchard staff, and restrict orchard access by machinery at critical times of the year (early season sprays and harvest).
- Driving through orchards or using equipment when soils are wet will result in rutting and soil compaction.
- Compacted soils are vulnerable to extreme weather (flooding and drought stress), and prevent roots from accessing nutrients and water, impacting crop growth.
- Wherever possible, avoid driving equipment through the orchards when soils are wet.
- Many orchard sites should be systematically tiled before planting. Some sites may be improved by installing an additional tile line between existing tiles. Make sure to avoid damaging tile lines when planting trees or installing support posts.
- This rainy spring will reveal issues with tiles that are not apparent in dry years, providing the opportunity to get them repaired later in the season after the soil has dried.
- Due to rainy conditions at harvest in recent years, New Zealand has initiated a study to examine orchard drainage – evaluate tools and technology that may benefit growers (O’Brien, 2019).
Considerations for planting trees in late spring
Maximizing tree survival and first year growth
- The root systems have less time to establish before warmer temperatures push bud development. Having more time for the roots to develop in the spring also helps with the trees’ resiliency and survival to hot and dry conditions
- Make sure roots are wet when planted.
- Water or irrigate individual trees post planting.
- Irrigation is very important for young trees through out the summer, especially with later planted trees which haven’t had as much time to establish their root system.
- Apply fertilizer as soon as possible to the newly planted trees, before bud break, to allow time for the fertilizer to leach down to the root zone during vegetative growth.
Late bloom considerations for pome fruit
- Newly planted trees will blossom later than established trees. Don’t forget to protect these trees from fire blight, especially if conditions are conducive for fire blight. OMAFRA has fire blight prediction maps for apples and pears.
Ontario Crop IPM, 2019. http://www.omafra.gov.on.ca/IPM/english/index.html
Wilson, K. 2000. Apple Rootstocks. http://www.omafra.gov.on.ca/english/crops/facts/00-007.htm
Hanlin, B. Caring for Bare Root Trees (Prior to Planting). 2014. https://wilkes.ces.ncsu.edu/2014/12/caring-for-bare-root-trees-prior-to-planting/