> For the complete documentation index, see [llms.txt](https://help.sbtinstruments.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.sbtinstruments.com/mpd/workflows/identify-optimal-inoculum-size/choose-best-seeding-ratio.md).
# Choose best seeding ratio
The measurements are now completed and it is time to choose the inoculation ratio that results in the best [High-quality culture](/mpd/cell-growth/high-quality-culture.md). In this 11-hour *E. coli* example, the 10-5 cryo stock dilution produces a culture that has likely just arrived at stationary stage. The 10-4 cryo stock dilution has a similar cell concentration but is less suitable due to being in the stationary phase longer. It therefore likely contains a higher proportion of cells that have lost culturability.
{% hint style="warning" %}
#### The inoculation ratio is only valid for the given cryo stock and growth parameters.
Conduct a new optimization experiment if there are any changes to cryo stocks, vessel type, broth, or incubation time.
{% endhint %}
## How to prepare high dilutions of the cryo stock
In the present example, a 10-5 dilution resulted in the best [High-quality culture](/mpd/cell-growth/high-quality-culture.md). This ratio is equivalent to a 1:100,000 dilution of the cryo stock, i.e substantially higher dilution than the typical 1:100 volumetric seeding ratio.
For future 11-hour overnight cultures, this would correspond to adding just 1 µL cryo stock to 100 mL (100,000 µL) growth medium. Because it it tricky to accurately pipette 1 µL we recommend that you first prepare a 1:100 dilution and then dilute this 1:1 000 for the final 1:100,000 dilution:
1. Prepare 1:100 dilution: Transfer 0.1 mL cryo stock to 9.9 mL sterile growth medium
2. Prepare 1:100,000 dilution: Transfer 0.1 mL 1:100 dilution to \~100 mL sterile growth medium in shake flask
## Summary and next steps
We hope that you are enjoyed the insights from this step by step guide. We are confident that your new and shiny [High-quality culture](/mpd/cell-growth/high-quality-culture.md) will improve your future bioprocesses.
Now that you have the conditions for a great starter culture try to [Track growth curve](/mpd/workflows/track-growth-curve.md) for it. For example, you could compare the [High-quality culture](/mpd/cell-growth/high-quality-culture.md) head-to-head with your previous starter culture protocol. You will likely observe a shorter lag phase duration for the [High-quality culture](/mpd/cell-growth/high-quality-culture.md).
---
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