Only partly. The capital must be invested or irrevocably committed before the I-526 or I-526E is filed, so some funds must move early. The farm itself can be kept until the immigrant visa is issued, but the family should not expect a firm date; petition processing and visa availability are both variable.
The money moves first; the family can move last
Hypothetical example: a Haldimand County couple wants to file EB-5, wait for approval, and only then sell the farm and relocate. The category's sequence permits part of that. Capital must be at risk at filing, so the investment funds, from the quota and any savings, must be committed before Form I-526E goes in, while the farm can remain in the family's hands.
After the petition is approved and a visa number is available, the family applies for immigrant visas at the consulate, attends interviews and medicals, and is admitted as conditional residents; the farm can be sold at any point in that window. What the couple cannot control is duration: USCIS processing times for investor petitions have historically been long, and set-aside categories can be faster or slower depending on demand. Plan the farm sale as a decision triggered by visa issuance, keep the operation running in the meantime, and remember that conditional residence brings its own two-year evidence requirement before permanent status is confirmed.