Starting artichokes from seed
Winter Lake Research Center recently received a contract
to grow a large number of artichoke plants from seed. The grower was
trying to establish a one acre plot of artichokes. Artichokes have a
reputation of being difficult to start from seed. The farmer had had
little success with starting his own plants. Another person was
contacted who agreed to start the plants. This other person met with
little success. Winterlake was contacted and agreed to do some
research on how to get artichoke seed to sprout reliably.
Many sprouting methods were tried until a
satisfactory sprouting rate of around 80% was achieved. The method
most successful was planting in small pots in a green house in early
spring.
It was found that the critical conditions were
temperature, dampness of the growing medium, sunlight and depth of
planting. The planting medium was a lesser concern.
The most successful planting medium was a
fifty/fifty mixture of very sandy loam and a commercial, organic soil
conditioner. This medium held some water but would not stay
saturated. This was important since the sprouting seeds need an even
water content that is not too wet, as excess moisture causes the
seeds to rot. Too little moisture drys them out quickly.
Peat pots and commercial plastic seed pots were both
tried. The peat pots allowed the seeds to sprout well, but the
maintenance was high. Any disruption in the watering schedule caused
plant death, as the peat pots dried out quickly. Small plastic pots
under three inches in diameter also sprouted the seeds well, while
keeping down the water related deaths. Pots smaller than three inches
allowed the plants to deplete the nutrients in the soil quickly and
also led to quicker root binding. The best pots were four inch and
larger plastic pots.
The artichokes were of the green globe variety. The
package said to plant them at a depth of one quarter inch. If planted
too shallow, the sprouts dried out and died. Sunlight plays a role in
the sprouting of these seeds, so planting too deeply resulted in a
low sprouting rate. It was found that the planting depth on the
package was correct and very critical to success.
The best seed sprouting rate was in full sun. The
optimum temperatures were found to be 70 to 80 degrees F in the
daytime with minimum night time temperatures of 50 degrees F. If the
plants are to be held in the pots more than three weeks after
sprouting, they need to be fed with a good balanced liquid
fertilizer.
It was found that the new plants should optimally be
planted within five weeks of sprouting to avoid root binding.