spindley plants

Talked to a neighbor, she said she can't garden, the plants won't grow. She showed me, looks like a lovely sunny spot. No walnut trees, a sort of moist area, not too much shade. Even the grass grows weird there. She said it used to grow well, but now the plant gel tall and spindley, put out tiny fruits, and fall over dead. That was tomatoes, other plants do similar, lettuces etc, tall, spindley, fall over dead.

I'm thinking something is depleted in her soil, but I can't come up with what right off. Any suggestions what I can look up for her?

Thanks!

I'm not sure but I'd be looking at a missing nutrient or a malicious element in the soil (persistent herbicide or something that came in with manure/compost/straw/etc)

Nutrient is my guess, she says she used no chemicals, and never added any straw or mulch, which would mean no inputs, and just strip mining the soil. Which would leave something low. The spindly then fall over dead seems like a pretty solid clue.

Maybe it would be a good idea to have the soil tested.  Are there mail order testing places?

I would suggest that she start adding things to the soil that would be a quick fix, like coffee grounds, compost  and leaf mold.