Green Planet Pro-Cal is an excellent supplemental source of Calcium, Magnesium and Iron. Plants engaged in rapid growth can often come up short on these essential elements so supplementation is a great idea. Pro-Cal is a popular choice in with plant growers.
Benefits of using Pro Cal include -
Here's a video from Green Planet giving an overview of Pro-Cal -
Green Planet Pro Cal is available from Addloes in a 1ltr bottle.