Want to avoid, minimize or even eliminate transplant shock and blossom end rot of your vegetable plants. Then read on.
Planting your starter plants in the spring is an event that I really look forward to. It marks a milestone for the spring outdoor garden and kicks off the annual garden enjoyment experience. Getting the plants in the ground and then caring for them till you can see some real growth is something I look forward to. However, transplant shock can slow the new growth, delay the fruiting process and the harvest. From living in a colder climate with a shorter growing season, I want to do everything I can to give my transplant a great start and avoid any delays in the growing process.
Everyone knows about hardening off. This is the process where the starter plant is adjusted to cooler outdoor temperatures over a period of a few days to a week or so, prior to planting. Certainly, a good idea and I encourage this to be done. I usually put my plants on a Radio Flyer pull wagon or cart that I can roll in and out of my sun room or garage when they are ready. If you purchased a starter plant, then they may have already been hardened off. Especially if they were purchased from a location that has outdoor racks of plants that are probably rolled under cover at night and back out into the sunny sales location during the stores hours of operation. If this is the case, then you may be able to make some hardening off duration adjustments. (Don’t overthink this, just go with your judgment).
But I think transplant shock is more about the roots than the leaves and stems. First, buy or grow your starter plant in larger pots, giving the roots room to expand and eliminate “root bound” conditions. The root ball should be solid when you carefully remove the plant from the pot. Just keep it well watered and the plant should come out of the pot with the root ball intact. And most important, is taking care to not have large swings in soil and root temperatures from the pot to the garden. Think about walking around in bare feet on cool ground or a cool day. Your feet get cold and you find yourself looking for some warms socks! Moving plants from a warm pot to the cool earth is no different. For most of us in cooler climates waiting until the soil is really warm enough for optimal root growth (60 degrees+ at a 6 to 10-inch depth) to avoid shock is just not feasible. Especially if you are planting a little deep, like tomatoes, to encourage root growth. So, my trick is to plant with hot water. This warms the soil from about 45 degrees to 70 degrees and avoids the “shock” of the plant being thrust into a cooler soil than the pot it was in.
And, to avoid blossom end rot on the tomatoes, I add calcium when planting. In order for the plant to take up the calcium or any nutrients at planting, the roots must be warm. So, using hot water makes the soil at the roots warmer and gives them that nutrient boost they need to stave off disease down the road.
To summarize:
- Purchase or grow plants in larger pots and keep them well watered so soil and the root ball stay firm.
- Harden off for a few days prior to planting.
- Prepare your beds as you normally would, you can even dig the plant holes ahead of time and let a day or two of sun warm the soil even deeper through the open hole.
- Keep roots warm by planting with hot water. I use the hottest tap water from my homes hot water heater, mixed with calcium and Miracle Gro water soluble fertilizer in a watering can. Fill the plant holes mid way with the hot water mixture.
- Test soil/water with your hand to make sure it is not too hot. The hot water mixture will cool quickly in the colder soil. Soil should not feel cold or hot to get best results. (The soil and water in the plant hole will cool down to about 70 pretty quick. And I use a kitchen digital meat thermometer to make sure the soil/water temperature is acceptable.)
- When the soil/water temp is around 70 complete the planting of the plant root ball. I also add a wall-o-water around the new transplant for added cold weather protection.
Please note that in a few cases I have experienced some wilting of the transplanted tomato plant immediately after the transplant. But I have left the plant alone and it recovers nicely in a couple of days.
