I have around 2 month old spinach planted in pots. A flowering shoot is coming out of one pot, out of which I have taken 4 harvests and in another repotted two weeks ago which are younger and only one harvest taken, two shoots are coming out. Is it overcrowding that is the culprit? Or is it something else? It is peak winter season here with temperatures being minimum 10 degrees Celsius and maximum 22 degrees celsius with somewhat sunny afternoons. Pots are 12 inch diameter at top.
Bolting ends leaf growth and speeds up the death of an annual after flowering, that's all*. It adds a little bitterness to the leaf but is not a contagious disease.
Growing cold-lovers in heat is the main culprit, not crowding. That's why spinach dishes are associated with cooler Florence (eggs florentine), and heat-loving tomatoes/eggplant with Southern Italy, Rome, Sicily.
Photographs also indicate you forgot to thin your seedlings, removing weaker plants.
*--Plants that flower have no interest as we do in its leaves, only to the degree of getting the critical mass of their factory to get to the flowering part. That's why they want to bolt and we don't like it.
