Growing Food with Hydroponics: Seed Germination Results

Here are the tools that I used to complete the seed germination observations—plastic tweezers (to keep from touching the seeds); a digital caliper (helps get accurate measurement of the leaf and root shoots); and the digital microscope (helps me see the seed germination process in much greater detail). When the seed coat is split and dropped, I was able to see inside the seed—amazing!

Observing seed germination and calculating the percent of seeds germinated in a batch of seeds are the learning objectives of the Seed Germination activity. This may sound like a straight-forward, maybe even boring task. However, I came up with a few unexpected results from my VNS Yellow Pea seed germination. Here’s what happened.

I picked the yellow pea seeds for the first batch of seeds to germinate. In past germination tests pea seeds have germinated very quickly, and in the Seed Dissection, the yellow pea seeds looked very beautiful under the digital microscope as the outer skin dropped off and the embryo, starch, leaves, cotyledon, and roots inside the seed became visible. Below are some of the more interesting images of the germinating yellow pea seeds.

Three different yellow field peas that were set up for germination at the same time and under the same conditions, but as the images show the seeds germinate at different rates

Comparing slow with fast germinating seeds—how are they different?

These two yellow pea seeds are similar in size, color, and appearance, but one seed is just starting to germinate, and the other seed has a root shoot longer than the seed diameter.

Calculating the germination rate

I was expecting the yellow pea seed germination rate to be between 90 and 95 percent based on previous experience and the germination rate documented from test data printed on the seed packaging. I was expecting all the pea seeds to have started germinating within the first 3-5 days of the set up. However, as Table 1 shows, only 60 percent of the pea seeds had germinated by day 7, and by day 10, the germination rate was still only 80 percent.

Table 1 – Seed Germination Data

SeedNumber of Seeds Number of Seeds Germinated by Day 7Number of Seeds Germinated by Day 10Percent of Seeds Germinated 
VNS Yellow Organic Field Pea(common name)
Pisum sativum (scientific name)
You can see how knowing the seed germination rate for each crop is very important to growers, because this affects how many plants will grow after being planted. Germination rates play an important role in predicting crop harvest yield. Seeds are expensive. The difference between a germination rate of 95 percent and 80 percent is compounded for plants grown on a large-scale. A 20 percent loss in plant germination leads to a significant crop loss and a large loss in earnings. 

Follow up questions

I had several questions that were not answered by my germination test. 

  • Why did the yellow field pea seeds have such a low germination rate? 
  • Did I do something in my set up that could have reduced the germination rate? 

I wanted to know if I messed up on some aspect of my germination test. I called the seed developer and talked to one of their horticulture experts. The company rep explained that large seeds can be more difficult to germinate because so much of the seed surface is exposed to the air. The larger seeds can dry up more quickly and they are also more susceptible to mold spores and other environmental factors. 

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WVU Extension, 4-H, PLANTS LLC, and Iowa State Univerity Extension partner on Growing Food with Hydroponics project.