Many gardeners have trouble with transplanting (especially in warmer climates) and lose their carefully raised seedlings to transplant shock.
While some amount of shock is inevitable at the time of transplanting (roots being disturbed and a change in conditions that the seedling is accustomed to), you can dramatically improve the survival rate by taking some precautions – both before and after the actual transplanting…
Here are some guidelines on how you can ensure a survival rate of 80-90% for even really warm climates – by reducing the shock that the seedlings experience.
1. Raising healthier vegetable seedlings – yourself
Good and healthy seedlings which are transplanted at the right time are the most likely to be healthy after transplanting and you should try to raise your own seedlings. This is better because you get to choose the varieties you grow (some are just more hardy) and also ensure that they are well cared for and timed right for transplanting.
Seedlings from nurseries can be unpredictable, depending on the care that has been taken with them in the 21-25 days before transplanting. Sometimes older seedlings don’t handle transplant shock well and are either slow to recover or unhealthy as a result – making them less productive.
For some tips on how to raise your own seedlings, please read “The basics of germinating vegetable seeds”.
2. Hardening your seedlings for a week before transplant
This is probably the most important step and is almost always overlooked by gardeners in the days leading up to the transplanting. The idea is to gradually get the seedling used to the lack of availability of water.
In order to do this, you should progressively reduce the watering starting from a week before your transplanting (see the diagram below for a sense on how this is to be done).
Schedule for hardening your saplings in the week before transplanting
3. Timing transplanting for the (cooler) afternoons
When you transplant is critical especially in warmer climates. In Indian cities along the coast (Mumbai, Mangalore, Goa, Kolkata, Goa and Chennai), transplanting at 10 AM is going to almost guarantee that the majority of your transplants will die.
However, if you do it late in the afternoon (perhaps 4:30 or 5:00 PM) the survival rate will increase by at least double. While the day temperatures in cooler climates like Bangalore may be much less harmful, it’s still a good idea to schedule your transplants for late afternoons.
4. Aiding moisture retention when/where you transplant.
One of the greatest contributors to transplant shock is the plant’s struggle to take up water and nutrition in the immediate aftermath of the transplanting activity.
The roots are disturbed and therefore it takes a while for uptake to resume and maintain the moisture in their “bodies”. Making sure that there is ample water available to them during the transition is the most important aspect of “hardening”.
The following steps will help improve water retention and availability for the transplanted seedlings:
- Seedlings must be watered heavily before uprooting from the nurseries where they have been growing.
- They should be kept carefully in the shade until transplanting
- Place a fistful of a 70:30 mix of coco-peat and compost into the pit where they are transplanted
- Water the soil around the seedlings roots deeply immediately after transplanting
- Be sure to mulch the soil around the base, retain moisture
5. Shelter the transplants from the heat for about a week
During the recovery period in the days after the transplant, shielding them from the heat of the sun can considerably assist their recovery.
A 50% grade shade net is quite useful and can temporarily be rigged to provide the shade necessary. As the image below shows, the plants (even lettuce) recovers considerably with this assistance.
Using 50% shade net to minimise transplant shock with lettuce