Alstroemeriat flower most abundantly in full sun (six to eight hours), but in sweltering climates, they will appreciate some shade during the peak of the afternoon sun. Like fertile, well drained soil. You can accomplish both qualities by improving your soil with an organic amendment, like compost or leaf mold. These plants do well in most ordinary garden soil but prefer a slightly acidic pH (5.5-6.5). Need regular moisture, especially as summer temperatures heat up.