diff --git a/conda/env.yaml b/conda/env.yaml
index 4a212d0753078f9e8d60157226e9372860aec81f..8199410ad7eb9b5213eecf47a35326dbacf70c09 100644
--- a/conda/env.yaml
+++ b/conda/env.yaml
@@ -6,5 +6,6 @@ channels:
 dependencies:
   - python >=3.7
   - numpy
+  - matplotlib
   - openalea.lpy
   - openalea.plantgl
diff --git a/conda/meta.yaml b/conda/meta.yaml
index 355d088d7991b342b9e129c580fb73de429e4a99..39fb396af36ccf9408c5a25fe73ddfbe056498a4 100644
--- a/conda/meta.yaml
+++ b/conda/meta.yaml
@@ -16,6 +16,7 @@ requirements:
   run:
     - python  {{ python }}
     - numpy
+    - matplotlib
     - openalea.lpy
     - openalea.plantgl