Hi Mike, This is an interesting topic. As the old beds start to degrade and sink, you can still turn it back into good soil without having to dig out the whole thing. I have a few thoughts (theoretical of course since I have not done this myself): Test the soil: After several years, take some of the old soil and send it to a soil lab (such as one at UC Davis or an extension service) and they will tell you how much amendment to adjust pH and maybe supplement with micronutrients. The extension service will help you with this, but of course they're trained on agriculture and you will have to use your own judgement on organic amendments. Improve drainage: Since the bed had sunken, you'd want to add more inorganics to improve drainage so the roots don't hit a muck layer. Top dress with fresh mix: This is where your plants will do most of the growing so provide fresh medium. I'd say overall though that a degraded bed can be brought back to nearly new conditions with fresh amendments. The only problem to keep an eye out for is viruses. I'm recalling horror stories that Alberto Castillo told in the past with virused plants infecting whole beds. Good luck and let me know how it turns out. Your Calochortus and other bulbs will be so happy - can't wait to see the pictures. Nhu On Jun 29, 2017 6:39 AM, "Michael Mace" <michaelcmace@gmail.com> wrote: For example, I have noticed that the soil level in the oldest bed has gradually declined, probably because the soil was 1/3 organic and that part is breaking down (the soil is equal parts sand, pea gravel, and planting mix). If I top-dress the bed with some organic matter, will that help to renew the soil, or am I kidding myself? <div dir="ltr"><div dir="auto"><div>Hi Mike,<br><br></div><div>This is an interesting topic. As the old beds start to degrade and sink, you can still turn it back into good soil without having to dig out the whole thing. I have a few thoughts (theoretical of course since I have not done this myself):<br><br>Test the soil: After several years, take some of the old soil and send it to a soil lab (such as one at UC Davis or an extension service) and they will tell you how much amendment to adjust pH and maybe supplement with micronutrients. The extension service will help you with this, but of course they're trained on agriculture and you will have to use your own judgement on organic amendments.<br><br>Improve drainage: Since the bed had sunken, you'd want to add more inorganics to improve drainage so the roots don't hit a muck layer.<br><br>Top dress with fresh mix: This is where your plants will do most of the growing so provide fresh medium.<br><br></div><div>I'd say overall though that a degraded bed can be brought back to nearly new conditions with fresh amendments. The only problem to keep an eye out for is viruses. I'm recalling horror stories that Alberto Castillo told in the past with virused plants infecting whole beds.<br><br></div><div>Good luck and let me know how it turns out. Your Calochortus and other bulbs will be so happy - can't wait to see the pictures.<br><br></div><div>Nhu<br></div><div><div class="gmail_extra"><br><div class="gmail_quote">On Jun 29, 2017 6:39 AM, "Michael Mace" <<a href="mailto:michaelcmace@gmail.com" target="_blank">michaelcmace@gmail.com</a>> wrote: <blockquote class="m_7430216739363603689quote" style="margin:0 0 0 .8ex;border-left:///1px/ #ccc solid;padding-left:///1ex/"> For example, I have noticed that the soil level in the oldest bed has gradually declined, probably because the soil was 1/3 organic and that part is breaking down (the soil is equal parts sand, pea gravel, and planting mix). If I top-dress the bed with some organic matter, will that help to renew the soil, or am I kidding myself?<br></blockquote></div></div></div></div> </div> _______________________________________________ pbs mailing list pbs@lists.pacificbulbsociety.net http://lists.pacificbulbsociety.net/cgi-bin/…