Baptisia australis (fasle indigo) is known to be difficult to grow seedlings. Several sources report that plants die during the transplanting and subsequent maturation process. Today’s post reports on my success rate for maturing these seedlings.
In a previous post I reported on a research project to determine the Best Way to Germinate Baptisia australis Seeds.
Germination of Baptisia australis Seed
The seeds were germinated in Ziploc snack bags containing some moistened paper towel. The seeds are quite large and it’s easy to see when a seed germinates. Such seeds were removed with tweezers and potted up in Pro-Mix soil, placing 1 to 4 seeds per 4 inch pot. If seeds are transferred as soon as the root radical appears, the success rate is usually quite high. Once a longer root is formed there is a higher risk that you damage the root during the transfer process. In cases were I have lots of seed, I will plant several in each pot, ensuring that I get at least 1 plant per pot.
Note: the seedlings in the picture are not B. australis, but both look very similar. The seedlings were left to grow a long root for demonstration purposes. I normally remove the seed long before the root gets this big.
The pots containing blue indigo are kept fairly wet and in 100% humidity by keeping them in a covered container with some water in the bottom. Once the seedlings show themselves above the soil line the humidity and water are slowly reduced so that the seedlings get used to room conditions. When outdoor temperatures are high enough at night (over 8 deg C), the plants are slowly moved outside and conditioned to full sun.
The pots are watered almost daily for a couple of weeks. I then transfer the seedlings into a pot containing local soil making sure that the roots are disturbed as little as possible. The pots now contain 1 or 2 seedlings each. Experience has shown that with most plant varieties, 2 seedlings per pot will result in at least 1 full size plant. The pots are then dug in the ground so that the soil level inside the pot is at about the same level as the ground soil. The benefit of sinking the pots in the ground is that they stay wet much longer and the roots stay cooler. Instead of needing water every day, they can be left for 4 or 5 days between watering.
End of Summer Results
It is now early September and the Baptisia seedlings from this past spring are doing fairly well. Fourteen pots out of 20 have at least 1 plant in them. That rate is a bit lower than my average for various seed types, but it is fairly good.
Normally, the seedlings will remain in their pots, in the ground, until spring. In this case I have been growing them for a naturalistic planting project and they were picked up in late fall for planting in the field.
I kept a few seedling pots for myself, and left them in the ground over winter. Most were doing fine in spring.