I want my seed script only be planted when on touch on ground. Please help?

So, I don't know how to use IsDescendantOf yet. So I am having problems that my seed can be planted on mid-air. I want my seed script functions when on touch on ground, and whether I use IsDescendantOf. It also won't touch the legal part to be planted. Please help? Without using the Touched Event? The seed will float on air and later be a plant which is so higher. And my seed script can be planted on different materials that in real life that real seeds won't be planted on different materials (except soil). So the player might complain why the seed can be planted in mid-air or in different materials or be confused that why the seed can be planted in different materials.

Script:

local t = game:GetService("TweenService")
local mouse = game.Players.LocalPlayer:GetMouse()
local pi = 3.14159265359
script.Parent.Deactivated:Connect(function()
	local oldseed = script.Parent
	local seed = script.Parent.Handle:Clone()
	seed.Parent = game.Workspace
	seed.CFrame = game.Players.LocalPlayer.Character.Starling_Seed.Handle.CFrame
	local explosion = Instance.new("Explosion", seed)
	mouse.Move:Connect(function()
		explosion.Position = Vector3.new(mouse.Hit.p.X, 0, mouse.Hit.p.Z)
	end)
	explosion.BlastRadius = pi
	print("Planted")
	seed.CanCollide = false
	wait(0.2)
	seed.Anchored = true
	oldseed:Destroy()
	wait(5)
	seed.Anchored = false
	local Mesh =  seed
	local boduy = Instance.new("BodyPosition", Mesh)
	boduy.MaxForce = Vector3.new(2000, 2000, 2000)
	boduy.Position = Vector3.new(seed.CFrame.X,100,seed.CFrame.Z)
	wait(2)
	Mesh.Anchored = true
	boduy:Destroy()
	while true do
		wait(5)
		local goal = {}
		goal.Size = Vector3.new(100.5, 50.96, 100.751)
		goal.Orientation = Vector3.new(90, game.Players.LocalPlayer.Character.HumanoidRootPart.CFrame.Y,90)
		goal.Color = Color3.fromRGB(255,0,0)
		local g = t:Create(Mesh, TweenInfo.new(50), goal)
		g:Play()
		wait(40)
		local newseed = game.Lighting.CloneSeedFruit.Starling_Seed:Clone()
		newseed.Handle.CFrame = Mesh.CFrame
		newseed.Parent = game.Workspace
		print("Cloned Seed!")
		g:Pause()
			local explosion3 = Instance.new("Explosion", seed)
			mouse.Move:Connect(function()
			explosion3.Position = Vector3.new(mouse.Hit.p.X, 0, mouse.Hit.p.Z)
		end)
		explosion3.BlastRadius = pi
		wait(3)
		explosion3:Destroy()
		explosion:Destroy()
	end
end)