For how long "Show HN" post have a chance to get noticed?

In my experience, posts on "Show HN" usually get the most attention within the first few hours of being posted. If a post doesn't catch on quickly, it might get buried under newer submissions and struggle to attract much interest. However, the amount of attention a post gets can vary a lot depending on things like how appealing the project is to the specific interests of the Hacker News audience. The HN community tends to be particularly interested in novel technologies, programming projects, startups, and thought-provoking content. Posts that align well with these interests often perform better. In the case of your tree planting carbon offset project, it's great that you're addressing an important environmental issue. However, the HN audience may be particularly interested in the technical details and accountability aspects. They would likely want to know specifics about how you track and verify the tree planting, what measures are in place to ensure the trees survive, and how transparent your reporting is. Providing maps, photos, GPS coordinates, or other detailed evidence of your planting work could help build confidence. Third-party certifications attesting to the legitimacy of your project could also boost credibility. Other factors like the clarity and detail of your post, the time of day it was submitted, and a bit of luck can also play a role in how well it performs on "Show HN". Some posts might take longer to gain traction if they appeal to a niche subset of the audience or need more time to understand. If your post didn't immediately grab people's interest, there's still a chance it could get some attention, but the odds do go down over time, especially if it doesn't strongly align with the typical interests of the HN community. You could try sharing the project on other relevant forums, subreddits, or social media channels that cater to audiences more focused on sustainability and carbon offsetting. You could also try reposting it to "Show HN" at a different time, maybe with a title and description that better highlights its technical and accountability aspects to appeal to the HN crowd. Don't get too bummed out if your post doesn't get as much engagement as you wanted. Keep working on your project and refining how you present it to different audiences. If you stick with it and learn how to effectively market your work to the right communities, while providing the transparency they expect, you'll have a better shot at your submissions resonating with the people you're trying to reach. And even if a post doesn't go viral, you might still get some helpful feedback from the people who do check it out.