Hi, Deborah -

Thank you for reaching out to the UNH Extension Infoline!

It sounds like you are off to a great start with your organic raised bed gardens. Mulching can provide many benefits such as soil moisture retention and suppression of annual weeds.

There are several good options for organic (e.g. non-plastic) mulches. Wood chips can be a good option. Note that mulches consume nitrogen as they break down. Because of the high carbon content of wood chip mulch, this may necessitate adding supplemental nitrogen. 

For more information about choosing a garden mulch, here is a link to a relevant fact sheet from UNH Extension: Garden Mulches [fact sheet] | Extension. I believe Coast of Maine does sell a variety of mulches, but Extension cannot make specific commercial recommendations.

I hope this information is helpful! Please feel free to reach out with any further questions.

Hi Deb, 

For clarity, what is your first question? You said, "I’ve heard that hardwood chips are preferable to one chips. Is. That correct?" 

Hardwood chips are great for use as garden mulch. Concerns over nitrogen lock-up are overblown and mostly only occurs when fresh wood chips are tilled into the soil instead of spreading out on the surface of soil. 

Chip mulch generally won't attract ants or other insects just by their nature although using any mulch increases the nooks and crannies that insects often like to use for shelter. You may, however, find white, thread-like mycelial hyphae growing in the mulch as some fungi like wood chips very much. This is not a cause for concern.  

Hardwood chips tend to break down faster than bark mulch which adds organic material to your soil. Chips will certainly be in line with organic standards as long as the mulch isn't treated with any chemicals such as dyes or preservatives. 

If you have further questions, please ask! 

Hi Deb, 

No worries about the typo. I don't think that there is a best option for mulch, it's more of a personal preference. As long as it covers the soil to prevent weeds and holds in moisture, it's doing what any mulch should do. Also, you do not need to age wood chips to use them on the surface of your soil.