You could, but it's not really necessary since you really need 5 attack for most of the game and that's 28 seeds you need to get back somehow, which tends to take a good chunk of time each level. Walling is only really helpful at the very end when you are okay with losing some seeds each round and eventually dying, because enemies can and will spawn inside your walls, and you have to be able to kill each of them almost immediately to have the space to avoid getting killed by their spawning circles. Walls mostly just save you from wasting moves on walking towards enemies and consequently from being surrounded.