Getting ready to plant several citrus and subtropical fruiting trees. What I want to do is self soil test for P.H ,NPK, and nematodes. I have too many sites to send samples off to a lab. Can anyone recommend a accurate soil test kit and are nematode visible with a inexpensive microscope. Thanks Mark
About the nematodes: I truly think it's not a matter of if you have em but more on how many in most cases as when you plant a tree they will come eventually. The best way to keep a tree healthy from nematodes is to have a rootstock that is not inviting to them, and to keep the tree well nourished... also, if you're planting more than one citrus think about the spacing between them, what variety it is to know which ones will grow bigger (sun).
To say the least, I would be more worried about how much sun, wind they will get; how much space will they have from each other ones they are grown to your liking and their abilities... also, if the other subtropical trees bring any pests, or are they friendly with them citrus (some trees just hate each other), and if they are grafted, I would want to know if the rootstock handles well on my area.
Hope this info helps you out a bit, happy gardening!