diff --git a/app/models/harvest.rb b/app/models/harvest.rb
index 8a05561f3..12b116296 100644
--- a/app/models/harvest.rb
+++ b/app/models/harvest.rb
@@ -39,13 +39,14 @@ class Harvest < ActiveRecord::Base
 
   ##
   ## Scopes
-  default_scope { joins(:owner).order(created_at: :desc) }
+  default_scope { joins(:owner) }
 
   ##
   ## Validations
   validates :crop, approved: true
   validates :crop, presence: { message: "must be present and exist in our database" }
   validates :plant_part, presence: { message: "must be present and exist in our database" }
+  validates :harvested_at, presence: true
   validate :crop_must_match_planting
   validate :harvest_must_be_after_planting
   validates :quantity, numericality: {
diff --git a/app/models/planting.rb b/app/models/planting.rb
index eeb880cda..2c788c047 100644
--- a/app/models/planting.rb
+++ b/app/models/planting.rb
@@ -96,7 +96,7 @@ class Planting < ActiveRecord::Base
 
   def expected_lifespan
     if planted_at.present? && finished_at.present?
-      return finished_at - planted_at
+      return (finished_at - planted_at).to_i
     end
     crop.median_lifespan
   end
@@ -114,13 +114,14 @@ class Planting < ActiveRecord::Base
   end
 
   def update_harvest_days
+    first_harvest = nil
+    last_harvest = nil
     if harvests.size.positive?
       # how long ago was this planted
-      first_harvest = (harvests.first.harvested_at - planted_at).to_i
-      last_harvest = finished? ? (harvests.last.harvested_at - planted_at).to_i : nil
-    else
-      first_harvest = nil
-      last_harvest = nil
+      first_harvest = (harvests.order(harvested_at: :asc).limit(1).first.harvested_at - planted_at).to_i
+      if finished?
+        last_harvest = (harvests.order(harvested_at: :desc).limit(1).first.harvested_at - planted_at).to_i
+      end
     end
     update(first_harvest: first_harvest, last_harvest: last_harvest)
   end
diff --git a/spec/models/planting_spec.rb b/spec/models/planting_spec.rb
index 0a744a92e..6d0910707 100644
--- a/spec/models/planting_spec.rb
+++ b/spec/models/planting_spec.rb
@@ -79,6 +79,59 @@ describe Planting do
     end
   end
 
+  describe 'planting first harvest preductions' do
+    context 'no data' do
+      let(:planting) { FactoryBot.create :planting }
+      it { expect(planting.crop.median_first_harvest).to eq(nil) }
+      it { expect(planting.first_harvest).to eq(nil) }
+      it { expect(planting.expected_lifespan).to eq(nil) }
+    end
+    context 'lots of data' do
+      def one_hundred_day_old_planting
+        FactoryBot.create(:planting, crop: planting.crop, planted_at: 100.days.ago)
+      end
+      before do
+        # 50 days to harvest
+        FactoryBot.create(:harvest, harvested_at: 50.days.ago, crop: planting.crop,
+                                    planting: one_hundred_day_old_planting)
+        # 20 days to harvest
+        FactoryBot.create(:harvest, harvested_at: 80.days.ago, crop: planting.crop,
+                                    planting: one_hundred_day_old_planting)
+        # 10 days to harvest
+        FactoryBot.create(:harvest, harvested_at: 90.days.ago, crop: planting.crop,
+                                    planting: one_hundred_day_old_planting)
+        planting.crop.plantings.each(&:update_harvest_days)
+        planting.crop.update_lifespan_medians
+        planting.crop.update_harvest_medians
+      end
+      it { expect(planting.crop.median_first_harvest).to eq(20) }
+    end
+    describe 'planting has no harvests' do
+      before { planting.update_harvest_days }
+      let(:planting) { FactoryBot.create :planting }
+      it { expect(planting.first_harvest).to eq(nil) }
+    end
+    describe 'planting has first harvest' do
+      let(:planting) { FactoryBot.create :planting, planted_at: 100.days.ago }
+      before do
+        FactoryBot.create :harvest, planting: planting, crop: planting.crop, harvested_at: 10.days.ago
+        planting.update_harvest_days
+      end
+      it { expect(planting.first_harvest).to eq(90) }
+      it { expect(planting.last_harvest).to eq(nil) }
+    end
+    describe 'planting has last harvest' do
+      let(:planting) { FactoryBot.create :planting, planted_at: 100.days.ago, finished_at: 1.day.ago, finished: true }
+      before do
+        FactoryBot.create :harvest, planting: planting, crop: planting.crop, harvested_at: 90.days.ago
+        FactoryBot.create :harvest, planting: planting, crop: planting.crop, harvested_at: 10.days.ago
+        planting.update_harvest_days
+      end
+      it { expect(planting.first_harvest).to eq(10) }
+      it { expect(planting.last_harvest).to eq(90) }
+    end
+  end
+
   it 'has an owner' do
     planting.owner.should be_an_instance_of Member
   end