I'm having some trouble interpreting the "random effects"-section in a summary generated from an lmer-model. I want to decide if my random effects are significant based on the output of summary, but I am not sure how to go about this. I have added my model and the summary()-output below.

**Model**

FertilizerModel <- lmer(root ~ fertilizer + week + fertilizer:week +(1+ week|plant:fertilizer))

**Output summary(FertilizerModel)**

```
Random effects:
Groups Name Variance Std.Dev. Corr
plant:fertilizer (Intercept) 0.0306727 0.17514
week 0.0007169 0.02677 1.00
Residual 0.2171683 0.46601
Number of obs: 60, groups: plant:fertilizer, 12
...
```